Unit 1 - Electrochemistry Diploma Questions

Electrochemistry review____ 1. When a substance undergoes oxidation, it always

a. loses electrons.b. decreases its oxidation numberc. becomes positively chargedd. attains a zero charge

Use the following equation to answer this question.

Cr2O72-(aq) + 14 H+(aq) + 3 Sn2+(aq) 3 Sn4+(aq) + 2 Cr3+(aq) + 7 H2O(l)

____ 2. The species reduced in this reaction is

a. Cr2O72-(aq)

b. Cr3+(aq)c. Sn2+(aq)d. Sn4+(aq)

____ 3. For the reaction,

2 Sn2+(aq) Sn(s) + Sn4+(aq)

a correct statement is that the

a. reaction is spontaneous.b. reaction involves a decrease in potential energy.c. Sn2+(aq) is both the oxidizing and reducing agent.d. Sn(s) is the oxidizing agent in this nonspontaneous reaction.

____ 4. A solution of acidified potassium permanganate is stored in an iron container. The net ionic equation for a reaction that occurs is

a. MnO4-(aq) + 8 H+(aq) + 5 K(s) Mn2+(aq) + 4 H2O(l) + 5 K+(aq)

b. 2 MnO4-(aq) + 16 H+(aq) + 5 Fe(s) 2 Mn2+(aq) + 8 H2O(l) + 5 Fe2+(aq)

c. MnO4-(aq) + 8 H+(aq) + Fe2+(aq) Mn2+(aq) + 4 H2O(l) + Fe3+(aq)

d. MnO4-(aq) + 8 H+(aq) + Fe(s) Mn2+(aq) + 4 H2O(l) + Fe2+(aq)

____ 5. In the compound Sb4O6(s), antimony has an oxidation state of

a. 0b. +3c. +4d. +6

____ 6. In the methane-oxygen fuel cell reaction

CH4(g) + 2 O2(g) CO2(g) + 2 H2O(g) E°net = +1.05 V

oxiation numbers show that

a. oxygen atoms lose electrons.

b. hydrogen atoms gain electrons.c. O2(g) is the reducing agent.d. carbon atoms lose electrons.

Use the following information to answer the next question.

Statement

F2(g) is a strong reducing agent.

Explanation

F2(g) has strong attraction for electrons.

____ 7. Based on this information, one should determine that

a. both the statement and the explanation are true, and that the explantion is correct for the statement.

b. both the statement and the explanation are true, but the explanation is not correct for the statement.

c. the statement is true, but the explanation is false.d. the statement is false, but the explanation is true.

____ 8. The spontaneous reaction will occur when ___i____ is mixed with ___ii___.

i iiA. Fe2+(aq) Pb2+(aq)B. Cr2+(aq) Sn2+(aq)C. Sn2+(aq) I2(s)D. Na+(aq) Pb(s)

Use the following chemical equations to answer the next question.

I. H2O(l) + H2SeO3(aq) SeO42-(aq) + 4 H+(aq) + 2 e-

II. 2 H+(aq) + N2O(g) + 2 e- N2(g) + H2O(l) III. H2(g) + N2O(g) + 2e- N2(g) + H2O(l) IV. H2SeO3(aq) + 4 H+(aq) + 2 O2(g) + 6 e SeO4

2-(aq) + 3 H2O(l)

____ 9. The two chemical equations for the half-reactions that would occur in the net redox reaction N2O(g) + H2SeO3(aq) N2(g) + SeO4

2-(aq) + 2 H+(aq) are

a. I and IIb. I and IIIc. II and IIId. II and IV

____ 10. An oxidation-reduction reaction that occurs in the human body is

a. H2CO3(aq) CO2(g) + H2O(l)

b. CH4(g) + 2 O2(g) CO2(g) + 2 H2O(g)c. C12H22O11(s) + 12 O2(g) 12 CO2(g) + 11 H2O(g)d. C6H12O6(aq) + 6 O2(g) 6 CO2(g) + 6 H2O(l)

____ 11. In balancing redox reactions, the coefficients assigned to the oxidizing agents and reducing agents make the equation consistent with which of the following statements?

a. Electron gain equals electron loss.b. Moles of reactants equal moles of products.c. Energy change of products equals energy change of reactants.d. Number of reactant molecules equals number of product molecules.

Use the following information to answer the next _ questions.

An iron ore sample was crushed and teated in order to convert all the iron to Fe2+(aq). This solution was then titrated with KMnO4(aq). The unbalanced redox equation for this reaction is

__MnO42-(aq) +__H+(aq) + __Fe2+(aq) __Mn2+(aq) + __H2O(l) + __ Fe3+(aq)

____ 12. The lowest whole number coefficients for the reactants in the balanced equation, in the order given, are

a. 1, 8, 1b. 1, 8, 5c. 2, 16, 5d. 5, 16, 2

____ 13. The titration required 55.0 mL of 0.100 mol/L KMnO4(aq) to react completely with the Fe2+(aq). The mass of iron in the ore sample was

a. 0.123 gb. 0.307 gc. 0.768 gd. 1.54 g

____ 14. During the titration,

a. the pH increases.b. Fe2+(aq) gains electrons.c. Fe2+(aq) acts as an oxidizing agent.d. the acidified MnO4

-(aq) acts as a reducing agent.

____ 15. An equation that represents a redox reaction is

a. NaOH(aq) + HCl(aq) NaCl(aq) + H2O(l)b. AgNO3(aq) + KI(aq) AgI(s) + KNO3(aq)c. Mg(OH)2(s) + H2SO4(aq) MgSO4(aq) + 2 H2O(l)d. Cu(s) + 4 HNO3(aq) Cu(NO3)2(aq) + 2 NO2(g) + 2 H2O(l)

____ 16. A spontaneous reaction would occur between 1.0 mol/L Fe3+(aq) solution and

a. I2(s)b. Zn(s)c. Hg(l)d. 1.0 mol/L Fe2+(aq)


Metals E(s), Q(s), R(s), and P(s) react with metallic ions to produce the following results:

Q2+(aq) + 2 R(s) Q(s) + 2 R+(aq) Q2+(aq) + E(s) no reaction 2 P+(aq) + E(s) 2 P(s) + E2+(aq)

____ 17. The strongest oxidizing agent is

a. R+(aq)b. Q2+(aq)c. E2+(aq)d. P+(aq)


A student titrated samples of sulfurous acid with a potassium permanganate solution. He obtained the following results:

Table 1. Volumes of 0.0310 mol/L KMnO4(aq) required to completely react with 100.0 mL samples of sulfurous acid.

Trial 1 2 3 4 Final buret reading (mL) 9.50 18.15 26.75 34.75 Initial buret reading (mL) 1.00 9.50 18.15 26.75 Final colour of mixture pink pink pink colorless

____ 18. The balanced net ionic equation for the titration is

a. 2 MnO4-(aq) + 5 H2SO3(aq) + 6 H+(aq) 2 Mn2+(aq) + 5 SO4

2-(aq) + 3 H2O(l)b. 2 MnO4

-(aq) + 5 H2SO3(aq) 2 Mn2+(aq) + 5 SO42-(aq) + 4 H+(aq) + 3 H2O(l)

c. 2 MnO4-(aq) + 5 H2SO3(aq) + 16 H+(aq) 2 Mn2+(aq) + 5 SO4

2-(aq) + 20H+(aq) + 3 H2O(l)d. 2 MnO4

-(aq) + 5 SO42-(aq) + 36 H+(aq) 2 Mn2+(aq) + 5 H2SO3(aq) + 13 H2O(l)

____ 19. The oxidation numbers for the metals in the oxides of TiO2(s), MoO3(s), W4O12(s), and W2O5(s) are, respectively,

a. 4, 6, 24, and 10b.

2, 3, 3, and

c. 4, 6, 6, and 5d.

2, 3, 24, and

____ 20. In the reaction

4 Zn(s) + 10 H+(aq) + NO3-(aq) NH4

+(aq) + 4 Zn2+(aq) + 3 H2O(l)

the reducing agent is

a. Zn(s)b. H+(aq)c. Zn2+(aq)d. NO3

-(aq)


A student observed the reactions between four different metals and the solutions of their ions, and recorded these “spontaneous” reactions.

I. W(s) + X+(aq) W+(aq) + X(s) II. X(s) + Y+(aq) X+(aq) + Y(s) III. Y(s) + Z+(aq) Y+(aq) + Z(s) IV. Z(aq) + W+(aq) Z+(aq) + W(s) V. X(s) + Z+(aq) X+(aq) + Z(s)

____ 21. If equation I is correct, which equation did the student record incorrectly?

a. IIb. IIIc. IVd. V

Use the following reactions to answer the next question.

Ir(s) + Tl+(aq) no reaction Ir3+(aq) + Re(s) no reaction 3 Tl+(aq) + Y(s) 3 Tl(s) + Y3+(aq)

____ 22. In these reactions, the strongest oxidizing agent is

a. Tl+(aq)b. Y3+(aq)c. Ir3+(aq)d. Re3+(aq)

____ 23. The compound that has an oxidation number for iodine that differs from that of the other three compounds is

a. H4I2O9

b. H5IO6

c. HIO4

d. HIO3


Four reducing agents listed in order of decreasing strength are W, Z, Y, and X.

Four statements about the reaction between the reducing agents and their respective oxidizing agents are:

I. W(s) + X2+(aq) W2+(aq) + X(s) II. Y(s) + X2+(aq) Y2+(aq) + X(s) III. W(s) + Z2+(aq) no reaction IV. Y(s) + Z2+(aq) Y2+(aq) + Z(s)

____ 24. The statement(s) inconsistant with the correct order of reducing agents is(are)

a. IV onlyb. III onlyc. I and IId. III and IV

____ 25. A redox reaction in which carbon is reduced is

a. 6 H2O(l) + 6 CO2(g) C6H12O6(aq) + 6 O2(g)b. HCO3

-(aq) + H3O+(aq) H2CO3(aq) + H2O(l)c. CH4(aq) + 2 O2(g) CO2(g) + 2 H2O(g)d. C6H12O6(aq) + 6 O2(g) 6 CO2(g) + 6 H2O(l)

____ 26. An example of a disproportionation reaction is

a. 2 NH3(aq) + NaOCl(aq) N2H4(aq) + NaCl(aq) + H2O(l)b. Cl2(aq) + H2O(l) HOCl(aq) + H+(aq) + Cl-(aq)c. 2 F2(g) + O2(g) 2 OF2(g)d. 2 Na(s) + I2(s) 2 NaI(s)

____ 27. Iodine solutions, which contain a suspension of I2(s), have a brown colour. Which of the following metals will not cause an iodine solution to change colour?

a. Ni(s)b. Cu(s)c. Ag(s)d. Mg(s)


A sample of Na2S2O3(aq) is titrated with acidified KMnO4(aq) to a pink endpoint.

One product of this redox reaction is SO42-(aq).

____ 28. A product of the reduction half-reaction is

a. H+(aq)b. Mn2+(aq)c. SO4

2-(aq)d. S2O3

2-(aq)


The reactions below involve hypothetical metals and metallic ions.

Reaction Observation

Z3+(aq) + X(s) no evidence of reaction X2+(aq) + D(s) evidence of reaction D+(aq) + A(s) evidence of reaction Z3+(aq) + D(s) no evidence of reaction A2+(aq) + Z(s) no evidence of reaction

____ 29. The order of oxidizing agents, from strongest to weakest, is

a. X2+(aq), Z3+(aq), A2+(aq), D+(aq)b. A2+(aq), Z3+(aq), D+(aq), X2+(aq)c. Z3+(aq), X2+(aq), A2+(aq), D+(aq)d. X2+(aq), D+(aq), Z3+(aq), A2+(aq)


Titration of 20.0 mL Samples of Acidified H2O2(l)with 0.15 mL KMnO4(aq)

Trial I II III IV Final Buret volume (mL) 18.3 34.6 17.4 33.8 Initial Buret volume (mL) 0.4 18.3 0.9 17.4 Colour at endpoint purple pink pink pink

____ 30. The balanced equation for the titration is

a. 2 MnO4-(aq) + 16 H+(aq) + 5 H2O2(l) 2 Mn2+(aq) + 8 H2O(l) + 5 O2(g)

b. 2 MnO4-(aq) + 6 H+(aq) + 5 H2O2(l) 2 Mn2+(aq) + 4 H2O(l) + O2(g)

c. 2 MnO4-(aq) + 6 H+(aq) + 5 H2O2(l) 2 Mn2+(aq) + 3 H2O(l) + 5 O2(g)

d. 2 MnO4-(aq) + 6 H+(aq) + 5 H2O2(l) 2 Mn2+(aq) + 8 H2O(l) + 5 O2(g)


Ethanol reacts with acidified permanganate ion, as represented by the equation

5 C2H5OH(l) + 4 MnO4-(aq) + 12 H+(aq) 5 CH3COOH(aq) + 4 Mn2+(a) + 11 H2O(l)

____ 31. In this reaction, the oxidation number for the oxidizing agent changes from

a. +7 to +2b. +28 to +8c. +2 to 0d. +10 to 0


In order to “hide” gold during the Second World War, Nobel Prize winner Neils Bohr “dissolved” the gold, stored it in a solution, and recovered it at the end of the war.

One way to “dissolve” gold is to react it with Aqua-Regia, a mixture of nitric and hydrochloric acids. The unbalanced equation for this reaction is

Au(s) + HNO3(aq) + HCl(aq) HAuCl4(aq) + H2O(l) + NO2(g)

____ 32. The atom that undergoes reduction in this reaction is

a. Aub. Hc. Nd. Cl

____ 33. When this equation is balanced using lowest whole number coefficients, the coefficient for nitric acid is

a. 2b. 3c. 4d. 5


Over 100 years ago, Gustave Eiffel designed the support structure for the Statue of Liberty. An iron framework was constructed and overlaid with copper sheets in such a way that the copper did not come into direct contact with the iron.

____ 34. The Statue of Liberty’s blue-green colour, which has developed over time, can be attributed to the

a. oxidation of solid iron into iron(II) ionsb. oxidation of solid copper into copper(II) ionsc. reduction of solid iron and solid copper into cationsd. reduction of oxygen gas and liquid water into hydroxide ions

____ 35. The Statue of Liberty’s blue-green colour, which has developed over time, can be attributed to the

a. oxidation of solid iron into iron(II) ionsb. oxidation of solid copper into copper(II) ionsc. reduction of solid iron and solid copper into cationsd. reduction of oxygen gas and liquid water into hydroxide ions

____ 36. A student was given three metal strips and was asked to identify each strip as lead, iron, or magnesium. The student labelled the strips X, Y, and Z and tested each strip in a Zn(NO3)2(aq) solution and a Ni(NO3)2(aq) solution. The student’s observations are shown below.

Evidence of Reaction

Zn(NO3)2(aq) Ni(NO3)2(aq)X no reaction black precipitateY black precipitate black precipitateZ no reaction no reaction

The metals X, Y, and Z are, respectively,

a. lead, iron, and magnesiumb. lead, magnesium, and ironc. iron, lead, and magnesiumd. iron, magnesium, and lead


Photochromic glass can be made by trapping silver chloride crystals and copper(I) ions in a glass matrix as the glass solidifies. When this type of glass is exposed to sunlight, the silver ions are converted into silver atoms, which cause the glass to darken. The two steps that occur in this chemical reaction are represented below.light Step I Ag+ + Cl- Ag + Cl Step II Cl + Cu+ Cu2+ + Cl-

The reaction in the second step prevents the chlorine atoms from escaping from the glass.

____ 37. In step II, the Cu+ ion acts as the

a. reducing agent and loses one electronb. oxidizing agent and gains one electronc. reducing agent and decreases in oxidation numberd. oxidizing agent and increases in oxidation number

____ 38. The half-reaction that causes the darkening of the glass is represented by the equation

a. Ag+ + e- Agb. Ag Ag+ + e-

c. Cl- Cl + e-

d. Cl + e- Cl-


To determine the concentration of Sn2+(aq) solution, a student titrated a 50.00 mL sample of acidified Sn2+(aq) with 1.44 mmol/L KMnO4(aq). The titration required 24.83 mL of KMnO4(aq) in order to reach a pale pink endpoint.

____ 39. The balanced net ionic equation for this titration is

a. 2 MnO4-(aq) + 16 H+(aq) + 5 Sn2+(aq) 2 Mn2+(aq) + 8 H2O(l) + 5 Sn4+(aq)

b. 2 MnO4-(aq) + 16 H+(aq) + 5 Sn2+(aq) 2 Mn2+(aq) + 8 H2O(l) + 5 Sn(s)

c. MnO4-(aq) + 8 H+(aq) + Sn2+(aq) Mn2+(aq) + 4 H2O(l) + Sn4+(aq)

d. MnO4-(aq) + 8 H+(aq) + Sn2+(aq) Mn2+(aq) + 4 H2O(l) + Sn(s)


The beautiful patterns of butterfly wings, the stripes on zebra pelts and the myriad of colours of tropical fish all result froom oscillating chemical reactions. These chemcial reactions can be studied in a much simpler form in the laboratory. In 1958, the Russian chemist B.P. Belousoz discovered a complet reaction sequence in which the concentration of reactants and products oscillated over time.

Unbalanced Reaction Equations I __H+(aq) + __BrO2

-(aq) + __ BrO3-(aq) __BrO2(aq) + __H2O(l)

II __Ce3+(aq) + __BrO2(aq) Ce4+(aq) + __BrO2-(aq)

III __BrO2-(aq) __BrO3

-(aq) + __BrO-(aq)

____ 40. In reaction II, the BrO2-(aq) underdoes

a. oxidation and gains one electron.

b. oxidaiton and loses one electron.c. reduction and gains one electron.d. reduction and loses one electron.

____ 41. In reaction III, the bromine in BrO2-(aq)

a. undergoes oxidation onlyb. undergoes reduction onlyc. both loses and gains protonsd. both loses and gains electrons


Common household bleach is an aqueous solution that contains approximately 5% sodium hypochlorite. The equilibrium involved in the production of bleach from chlorine can be represented by the reaction equation

Cl2(g) + 2 OH-(aq) ClO-(aq) + Cl-(aq) + H2O(l)

____ 42. In the production of bleach, the reduction half-reaction is

a. Cl2(g) + 2 e- 2 Cl-(aq)b. 2 Cl-(aq) Cl2(g) + 2 e-

c. 4 OH-(aq) O2(g) + 2 H2O(l) + 4 e-

d. ClO-(aq) + H2O(l) + 2 e- Cl-(aq) + 2 OH-(aq)

____ 43. A student has one coin made of copper and one coin made of nickel. Which of the following solutions could the student use to demonstrate which of these metals is the stronger reducing agent?

a. Hg2+(aq)b. Fe3+(aq)c. Fe2+(aq)d. Sn4+(aq)


Poisonous oxalic acid is found in non-toxic concentrations in vegetables such as spinach and rhubarb. Manufacturers of spinach juice are required to analyze the concentrations of oxalic acid to avoid problems that could arise from unexpectedly high concentrations of oxalic acid. The reaction of oxalic acid with acidified potassium permanganate can be represented by the following equation.

5 HOOCCOOH(aq) + 2 MnO4-(aq) + 6 H+(aq) 2 Mn2+(aq) + 8 H2O(l) + 10 CO2(g)

____ 44. If 15.0 mL of oxalic acid solution is completely reacted with 20.0 mL of 0.0015 mol/L acidified permanganate solution, then the oxalic acid concentration will be

a. 8.0 x 10-4 mol/Lb. 2.4 x 10-3 mol/Lc. 5.0 x 10-3 mol/Ld. 6.0 x 10-3 mol/L

____ 45. A technician reacting oxalic acid with acidified potassium permanganate is not likely to observe

a. an increase in electrical conductivityb. a visible colour changec. a slight increase in pHd. the formation of a gas

____ 46. Acidic permanganate solutions and acidic dichromate solutions are often used in redox titrations because they are strong

a. reducing agents that change colour when they are reduced.b. reducing agents that change colour when they are oxidized.c. oxidizing agents that change colour when they are reduced.d. oxidizing agents that change colour when they are oxidized.


Electronic circuit boards can be made by etching a copper board that is coated with plastic on one side. A special masking tape is applied to the surface of the copper board in the shape of the desired circuit pattern. The circuit board is then etched by reacting it with FeCl3(aq) to remove the unwanted copper.

____ 47. The net equation for the spontaneous reaction that occurs when the circuit board is immersed in the FeCl3(aq) is

a. Fe2+(aq) + Cu(s) Cu2+(aq) + Fe(s)b. Cu+(aq) + Fe2+(aq) Fe3+(aq) + Cu(s)c. 2 Fe3+(aq) + Cu(s) Cu2+(aq) + 2 Fe2+(aq)d. 2 Fe3+(aq) + 3 Cu(s) 3 Cu+(aq) + 2 Fe(s)

____ 48. In this reaction, the copper acts as the

a. oxidizing agent and is oxidized.b. oxidizing agent and is reduced.

c. reducing agent and is oxidized.d. reducing agent and is reduced.

____ 49. Which of the following statements and corresponding net voltages are correct for this reaction?

a. It is a spontaneous reaction with a E°net = +0.43 V.b. It is a spontaneous reaction with a E°net = +1.11 V.c. A power supply is required because the E°net = - 0.43 V.d. A power supply is required because the E°net = - 1.11 V.


At one time, an aqueous solution of formaldehyde called formalin(CH2O(aq)) was used as a disinfectant and as a tissue preservative. Today, formalin is commonly used in the industrial preparation of plastics and resins.

Formalin can be produced by reacting methanol with acidified potassium dichromate, as represented by the following unbalanced equation.

__CH3OH(l) + __Cr2O72-(aq) __H+(aq) CH2O(aq) + __Cr3+(aq) + __H2O(l)

____ 50. When the above equation is balanced, the equation is

a. CH3OH(l) + Cr2O72-(aq) + 14 H+(aq) CH2O(aq) + 2 Cr3+(aq) + 7 H2O(l)

b. 3 CH3OH(l) + Cr2O72-(aq) + 14 H+(aq) 3 CH2O(aq) + 2 Cr3+(aq) + 7 H2O(l)

c. 3 CH3OH(l) + Cr2O72-(aq) + 8 H+(aq) 3 CH2O(aq) + 2 Cr3+(aq) + 7 H2O(l)

d. 3 CH3OH(l) + Cr2O72-(aq) + 8 H+(aq) 3 CH2O(aq) + 2 Cr3+(aq) + 8 H2O(l)


A sample of Na2S2O3(aq) is titrated with acidified KMnO4(aq) to a pink endpoint. One product of this redox reaction in SO4

2-(aq).

____ 51. A product of the half-reaction is

a. H+(aq)b. Mn2+(aq)c. SO4

2-(aq)d. S2O3

2-(aq)

____ 52. A student used an acidified 6.31 x 10-2 mol/L KMnO4(aq) solution to titrate 25.0 mL samples of Fe2+(aq) solution of unknown concentration. In the reactions, the Fe2+(aq) ion was oxidized to the Fe3+(aq) ion. The student completed five trials and summarized the data in a table.

Trial Number 1 2 3 4 5Final Buret

Reading (mL)17.55 35.65 26.40 42.65 16.85

Initial Buret Reading (mL)

0.30 17.55 10.05 26.40 0.55

Final Colour purple purple pink pink pink

According to the student’s data, the concentration of Fe2+(aq) is

a. 0.206 mol/Lb. 0.218 mol/Lc. 0.213 mol/Ld. 0.223 mol/L


Kawneer, a company in Lethbridge, processes aluminium “logs” for commercial use. The first step in the process involves removing the natural aluminium oxide coating from the logs.

____ 53. Once the protective coating has been removed, the Al(s) surface undergoes a redox reaction with H2O(l). In this reaction,

a. H2(g) is evolved and the solution becomes basicb. O2(g) is evolved and the solution becomes basicc. H2(g) is evolved and the solution becomes acidicd. O2(g) is evolved and the solution becomes acidic


U3+(aq) + La(s) La3+(aq) + U(s) Y3+(aq) + U(s) no reaction Y3+(aq) + La(s) La3+(aq) + Y(s)

____ 54. The oxidizing agents above, listed from strongest to weakest, are

a. U3+(aq), La3+(aq), Y3+(aq)b. U3+(aq), Y3+(aq), La3+(aq)c. Y3+(aq), U3+(aq), La3+(aq)d. U(s), Y(s), La(s)


Standard Reduction Potentials

VO2+(aq) + 2 H+(aq) + e- VO2+(aq) + H2O(l) E° = +0.999 V

VO2+(aq) + 2 H+(aq) + e- V3+(aq) + H2O(l) E° = +0.340 V VO2

+(aq) + 4 H+(aq) + 5 e- V(s) + 2 H2O(l) E° = - 0.250 V

V3+(aq) + e- V2+(aq) E° = - 0.255 V

____ 55. Which of the following substances is the strongest reducing agent?

a. V2+(aq)b. V3+(aq)c. VO2

+(aq)d. VO2+(aq)

____ 56. In the balanced redox reaction equation3 Cu(s) + 2 NO3

-(aq) + 8 H+(aq) 3 Cu2+(aq) + 2 NO(g) + 4 H2O(l)the oxidation number of nitrogen

a. decreases by 3b. inceases by 3c. increases by 2d. decreases by 6

____ 57. In a reaction, Sn2+(aq)

a. will undergo oxidation when combined with Pb(NO3)2(aq)b. acts as a reducing agent when combined with Ni(s)c. always acts as an oxidizing agentd. acts as an oxidizing agent when combined with Cd(s)

____ 58. A redox reaction occurs when an iron nail is placed in a solution of copper(II) sulfate. Elemental copper begins to form, and the colour of the solution changes. In this reaction, the reducing agent is

a. Fe(s)b. Cu(s)c. Fe2+(aq)d. Cu2+(aq)


To prevent it from contaminating the air, chlorine gas can be reacted as representedby the unbalanced equation

Cl2(g) + S2O32-(aq) + H2O(l) SO42-(aq) + H+(aq) + Cl-(aq)

____ 59. The balanced oxidation half-reaction for this change is

a. H2O(l) + S2O32-(aq) SO42-(aq) + 4 e- + 2 H+(aq)

b. Cl2(g) + 2 e- 2 Cl-(aq)c. 5 H2O(l) + S2O3

2-(aq) 2 SO42-(aq) + 10 H+(aq) + 8 e-

d. 5 H2O(l) + S2O32-(aq) + 4 e- 2 SO42-(aq) + 10 H+(aq)


In a laboratory, a student obtained the following results when testing, under standard conditions, reactions between various metals and their corresponding ions.

Ga(s) Fe(s) Zn(s) Mg(s)Ga3+(aq) - KeyFe2+(aq) - reactionZn2+(aq) - reactionMg2+(aq) - - no test perfomed

____ 60. The reduction potential of the Ga3+(aq) could be

a. - 0.53 Vb. - 1.41 Vc. +1.21 Vd. +1.92 V


The following reaction will occur at high temperatures.

2 Na(g) + Cl2(g) 2 NaCl(g) + energy

____ 61. The half-reaction for the reduction that occurs in this reaction

a. Na(g) Na+(g) + e-

b. Na(g) + e- Na+(g)c. Cl2(g) + 2 e- 2 Cl-(g)d. Cl2(g) 2 Cl-(g) + 2 e-

____ 62. Four metals represented by the symbols R, S, T, and V and their ions combine with each other in the following manner:

S2+(aq) + 2 T(s) 2 T+(aq) + S(s) R3+(aq) + T(s) No Reaction 2 R3+(aq) + 3 V(s) 2 V2+(aq) + 2 R(s)When the oxidizing agents are arranged from strongest to weakest, the order is

a. S2+(aq), T+(aq), R3+(aq), V2+(aq)b. V2+(aq), R3+(aq), T+(aq), S2+(aq)c. V(s), R(s), T(s), S(s)d. S(s), T(s), R(s), V(s)

____ 63. In the reaction of sodium metal with water, the reduction half-reaction produces ___i___, which results in a pH ___ii____ than 7.

The row that best completes the statement above is

i iiA. hydroxide ions greaterB. hydroxide ions lessC. hydrogen gas greaterD. hydrogen gas less


A student dipped 12.50 g strips of four different metals, Ag(s), Cu(s), Pb(s), and Mg(s), into a beaker containing 250 mL of 1.00 mol/L HCl(aq) in order to determine an activity series. One of the metals reacted immediately and vigorously with the acid.

____ 64. The balanced net ionic equation for the first reaction that occurred is

a. 2 Ag(s) + 2 H+(aq) H2(g) + 2 Ag+(aq)b. Cu(s) + 2 H+(aq) H2(g) + Cu2+(aq)c. Pb(s) + 2 H+(aq) H2(g) + Pb2+(aq)d. Mg(s) + 2 H+(aq) H2(g) + Mg2+(aq)

____ 65. The following data were collected during a redox laboratory investigation.

W(s) X(s) Q(s) Z(s) Key evidence of

reaction no evidence of

reaction

W-(aq) X2-(aq) Q2-(aq) Z3-(aq)

In this investigation, the responding variable is the

a. reducing agentb. oxidizing agentc. evidence of reactiond. time required for reaction

____ 66. Which of the following aqueous ions can either gain or lose electrons in a redox reaction?

a. Sn2+(aq)b. Cl-(aq)c. Ca2+(aq)d. S2-(aq)

____ 67. The equation representing a spontaneous reaction at standard conditions is

a. Co2+(aq) + 2 Fe2+(aq) Co(s) + 2 Fe3+(aq)b. Sn4+(aq) + 2 Br-(aq) Sn2+(aq) + Br2(l)c. 2 I-(aq) + Cl2(g) I2(s) + 2 Cl-(aq)

d. Pb(s) + Fe2+(aq) Pb2+(aq) + Fe(s)

____ 68. Two reagents that will oxidize Pb(s) to Pb2+(aq) but that will not oxidize I-(aq) to I2(s) are

a. F2(g) and Fe3+(aq)b. Fe3+(aq) and Br2(l)c. Cd2+(aq) and Ag+(aq)d. Cu2+(aq) and Sn4+(aq)

____ 69. Bacteria in our mouths and digestive systems convert sodium nitrate and other nitrate salts into nitrites, as indicated by the imcomplete and unbalanced half-reaction NaNO3(aq) NaNO2(aq). In this half-reaction,

a. the oxidation number for sodium changes from -9 to -7b. the oxidation number of nitrogen increasesc. the oxidation number of oxygen increasesd. reduction occurs

____ 70. Metals W(s), X(s), Y(s), and Z(s) were placed in solutions of each of their respective ionic salts. The results are summarized in the data table below.

X+(aq) Y2+(aq) Z3+(aq) W+(aq) - evidence of reaction

- no evidence of reaction

X(s) Y(s) Z(s) W(s)

According to the results, the strongest reducing agent is

a. Y2+(aq)b. W(s)c. Y(s)d. W+(aq)


Owners of an acreage had their well water analyzed by the Alberta Research Centre. The well water was found to contain Cl-(aq), I-(aq), Fe2+(aq), NO3

-(aq), Ni2+(aq), Zn2+(aq), Ca2+

(aq), and Na+(aq).

____ 71. To carry water from the well to their home, the owners should choose a metal pipe made of

a. Fe(s)b. Cu(s)c. Cr(s)d. Al(s)

____ 72. A researcher wants to test aluminium, zinc, chromium, and copper individually for their suitablility as a dental filling. Keeping in mind many foods are acidic, which metal would be most suitable to investigate as a filling?

a. aluminiumb. zincc. chromiumd. copper

____ 73. Given the reactions

2 X-(aq) + Y2(s) X2(s) + 2 Y-(aq) 2 Z-(aq) + Y2(s) no reaction 2 Z-(aq) + W2(s) Z2(s) + 2 W-(aq)

another spontaneous reaction would be

a. Z2(s) + 2 X-(aq) X2(s) + 2 Z-(aq)b. X2(s) + 2 Y-(aq) 2 X-(aq) + Y2(s)c. X2(s) + 2 W-(aq) 2 X-(aq) + W2(s)d. Y2(s) + 2 W-(aq) 2 Y-(aq) + W2(s)


A thermite reaction is a highly exothermic process that is used in welding massive objects such as ship propellers and train rails. The reaction can be represented by the equation

2 Al(s) + Fe2O3(s) Al2O3(s) + Fe(l)

____ 74. In this thermite reaction, the substance that undergoes oxidation is

a. ironb. aluminiumc. iron(III) oxided. aluminium oxide

Use the following standard electrode potentials to answer the next question.

Reduction ElectricalHalf-Reaction Potential (V)

PbO2(s) + SO42-(aq) + 4 H+(aq) + 2 e- PbSO4(s) + 2 H2O(l) +1.69O2(g) + 2 H2O(l) + 4 e- 4 OH-(aq) +0.40

NiO2(s) + 2 H2O(l) + 2 e- Ni(OH)2(s) + 2 OH-(aq) - 0.49Zn(OH)4

2-(aq) + 2 e- Zn(s) + 4 OH-(aq) - 1.20

____ 75. In the half-reactions above, the strongest oxidizing agent is the

a. PbO2(s), SO42-(aq), and H+(aq) combination

b. O2(g) and H2O(l) combinationc. Zn(OH)4

2-(aq)d. OH-(aq)

Use the following standard electrode potentials to answer the next question.

Reduction Half-Reaction Electrical Potential (V)

X3+(aq) + 3 e- X(s) +1.95 Q(l) + e- Q-(aq) +0.61

Y2+(aq) + e- Y+(aq) +0.02M(s) + 3 e- M3-(aq) - 0.25

____ 76. Which of the following tables identifies, with checkmarks (), the spontaneous reactions that would be predicted given the half-reactions shown above?

a. c.

b. d.

____ 77. At API Grain Processors in Red Deer, Alberta, tanks used in the fermentation of wheat are sterilized using ClO2(aq). The balanced half-reaction that represents the change that occurs when ClO2(aq) changes to Cl-(aq) in an acidic solution is

a. 2 ClO2(aq) + 8 H+(aq) 2 Cl-(aq) + 4 H2O(l) + 6 e-

b. ClO2(aq) + 6 H+(aq) Cl-(aq) + 3 H2O(l) + 5 e-

c. ClO2(aq) + 4 H+(aq) + 4 e- Cl-(aq) + 2 H2O(l)d. ClO2(aq) + 4 H+(aq) + 5 e- Cl-(aq) + 2 H2O(l)


Nova Chemicals is a major producer of ethene in Alberta. Ethene is produced by thermally cracking ethane that has been separated from natural gas. The following equation represents the cracking process.

C2H6(g) C2H4(g) + H2(g)

____ 78. In the cracking process, the oxidation number of

a. carbon changes from -2 to -3b. carbon changes from -3 to -2c. hydrogen changes from 0 to +1d. hydrogen increases and decreases

____ 79. If the reference half-cell was changed to the standard nickel half-cell, the reduction potential of a standard bromine half-cell would be

a. +0.26 Vb. +0.81 Vc. +1.07 Vd. +1.33 V


An AgO-Cd cell is used in satellite batteries. This cell is very compact and it can supply a great deal of energy. Relevant equations for this cell are

2 AgO(s) + H2O(l) + 2 e- Ag2O(s) + 2 OH-(aq) E° = + 0.61 V Cd(OH)2(s) + 2 e- Cd(s) + 2 OH-(aq) E° = - 0.81 V

____ 80. The E°net value for this cell is

a. -1.42 Vb. -0.20 Vc. +0.20 Vd. +1.42 V

____ 81. In a functioning electrochemical cell,

a. anions migrate inside the cell from the anode to the cathode.b. cations migrate inside the cell from the cathode to the anode.c. electrons move in the external circuit from the anode to the cathode, where reduction

occurs.d. electrons move in the external circuit from the cathode to the anode, where reduction

occurs.

____ 82. An electrolytic cell contains 2.00 mol/L NiCl2(aq) and operates at 0.500 A. In order to plate 5.87 g of Ni(s), the cell will have to operate for

a. 1.93 x 104 sb. 3.86 x 104 sc. 7.72 x 104 sd. 1.54 x 105 s

____ 83. The cell capable of recarging a 1.25 V battery is

a. Ag(s)|Ag+(aq)||Cu2+(aq)|Cu(s)b. Al(s)|Al3+(aq)||Sn2+(aq)|Sn(s)c. Co(s)|Co2+(aq)||Pb2+(aq)|Pb(s)d. Fe(s)|Fe2+(aq)||Ni2+(aq)|Ni(s)


Corrosion of iron causes billions of dollars in damage every year. A reaction that occurs during corrosion is

4 Fe(s) + 3 O2(g) + 6 H2O(l) 4 Fe(OH)3(s) + energy

____ 84. The oxidizing agent in this reaction is

a. Fe(s)b. O2(g)c. H2O(l)d. Fe(OH)3(s)

____ 85. One reason that copper pipes rather than iron pipes are used in household plumbing is that

a. iron has a greater tendency to be oxidized than copper.b. iron will react with dissolved minerals such as calcium salts.c. copper is a better conductor of heat energy than iron.d. commercial drain cleaners containing sodium hydroxide will react with iron.


Galvanizing, a process used to prevent corrosion, involves coating iron metal with a thin layer of zinc metal.

____ 86. Iron nails can be galvanized using an electrolytic process. The nails to be galvanized would be attached to the

a. anodeb. electrode at which anions reactc. electrode at which oxidation occursd. electrode at which reduction occurs

____ 87. A galvanized nail was placed in a copper(II) sulfate solution. After a day, the blue colour of the solution disappeared and copper metal was produced. The procedure was repeated with objects made of other metals. Similar results would not be predicted for

a. an uncoated iron nailb. a chromium-plated spoonc. a nickel-plated coin

d. a gold-plated bracelet

____ 88. In a voltaic cell,

a. chemical energy is converted to electrical energy in a spontaneous change.b. chemcial energy is coverted to electrical energy in a non-spontaneous change.c. electrical energy is converted to chemical energy in a spontaneous change.d. electrical energy is converted to chemical energy in a non-spontaneous change.

____ 89. One way in which voltaic cells differ from electrolytic cells is that

a. anions migrate to the anode in one but to the cathode in the other.b. oxidation occurs at the cathode in one but at the anode in the other.c. voltaic cells have an external circuit but electrolytic cells do not.d. the cell potential for one is positive but negative for the other.


A student contructed the following cell and recorded her observations.

Observations: I. The voltmeter registers 1.32 V. II. The mass of electrode M decreases. III. The colur or X-(aq) becomes more intense. IV. The colour of M+(aq) ion becomes more intense.

____ 90. The oxidation half-reaction for the voltaic cell shown would be

a. 2 X-(aq) X2(g) + 2 e-

b. X2(g) + 2 e- 2 X-(aq)c. M(s) M+(aq) + e-

d. M+(aq) + e- M(s)

____ 91. Which of the following observations would not identify the oxidizing agent?

a. Observation Ib. Observation IIc. Observation IIId. Observation IV

____ 92. Electrolytic cells are used commercially in

a. camerasb. fuel cellsc. flashlightsd. metal plating


The electrolyis of molten sodium chloride (NaCl(l)) in the Downs Cell and the electrolysis of brine (NaCl(aq)) are two important industrial applications of electrolysis. They produce large quantities of chlorine gas, hydrogen gas, sodium hydroxide, and sodium metal. All of these products have important industrial uses. The design of these cells is illustrated below.

____ 93. In both cells, the design is such that the products of the electrolysis reactions are removed. If the products were not removed, they would

a. react with the original reactantsb. react with the electrodesc. react spontaneously with each otherd. react with the electrolytes

____ 94. The Downs Cell operates at a high temperature so that the sodium chloride is maintained in the liquid state. The design of this cell suggests that

a. Cl2(l) is very soluble in NaCl(l)b. Na(l) is less dense than NaCl(l)c. Na(l) is soluble in NaCl(l)d. Na(l) could react spontaneously with NaCl(l)

____ 95. Sodium metal is not produced in the electrolysis of brine because

a. Na(s) reacts smpontaneously with H2O(l)b. Cl-(aq) is more readily reduced than Na+(aq)c. H2O(l) is more readily oxidized than Cl-(aq)d. H2O(l) is more readily reduced than Na+(aq)

____ 96. An electron flow of 12.0 A is used in the electrolysis of molten sodium chloride. The time required to produce 1.00 kg of Na(l) is

a. 2.23 hb. 48.6 hc. 97.2 hd. 194 h

____ 97. The products of the electrolysis of brine can be used to produce HCl(g). A saturated solution of HCl(aq) has a concentration of 12.2 mol/L. What mass of NaCl(s) must be consumed to produce 100 L of this HCl(aq)?

a. 44.5 kgb. 71.3 kgc. 89.0 kgd. 143 kg


Corrosion of iron costs the public millions of dollars annually. The corrosion process can be simply represented by two half-reactions:

Fe(s) Fe2+(aq) + 2 e-

O2(g) + 2 H2O(l) + 4 e- 4 OH-(aq)

The Fe(OH)2(s) that forms if futher oxidized by O2(g) in the presence of water to form rust, a mixture of hydrated oxides that is represented by the general formula Fe2O3•xH2O(s).

One region on the iron surface acts as the anode, and another region, whre the wet iron is exposed to oxygen, acts as the cathode.

____ 98. Under standard conditions, the net voltage for the oxidation-reduction reaction that results in the formation of Fe(OH)2(s) is

a. - 0.85 Vb. +0.85 Vc. - 1.30 Vd. +1.30 V

____ 99. Iron is often alloyed with zinc to minimize corrosion. The zinc in the alloy acts as the

a. anode and is oxidized.b. anode and is reduced.c. cathode and is oxidized.d. cathode and is reduced.

____ 100. Salt spread on highways during the winter months increases the rate of rust formation on cars because the salt

a. reacts with the rust to form iron salts.b. reacts with the iron salts to form iron.c. increases the conductivity of the electrolyte solution.d. decreases the conductivity of the electrolyte solution.


Leaching technology is used in the mining and refining of copper ore. In the first step of the leaching process, sulfuric acid flows through a copper ore deposit. Under ideal conditions, the copper metal in the ore reacts with the concentrated sulfuric acid to form copper(II) ions. The resulting copper(II) slurry is transferred to an electrolytic cell where pure copper is produced. (Assume that the sulfuric acid completely ionizes to hydrogen ions and sulfate ions.)

____ 101. A non-spontaneous reaction may occur if the concentrations are manipulated. The balanced net ionic equation for the reaction of copper metal with sulfuric acid under these ideal conditions is

a. Cu(s) + SO42-(aq) + 4 H+(aq) Cu2+(aq) + H2SO3(aq) + H2O(l)

b. Cu2+(aq) + H2S(aq) Cu(s) + 2 H+(aq) + S(s)

c. Cu(s) + H2S(aq) Cu2+(aq) + H2(g) + S2-(aq)d. Cu(s) + 2 H+(aq) Cu2+(aq) + H2(g)

____ 102. What mass of pure copper is produced from the electrolysis of ecess copper(II) ions over a 24.0 hour period when the cell is operated at 100 A?

a. 2.84 kgb. 5.69 kgc. 11.4 kgd. 549 kg

____ 103. The net ionic equation for the conversion of copper(II) oxide in copper ore isCuO(s) + 2 H+(aq) Cu2+(aq) + H2O(l)

The copper in the copper(II) oxide is

a. reducedb. oxidizedc. the oxidizing agentd. neither oxidized nor reduced

____ 104. In the Hall-Heroult process, aluminium is produced by the electrolysis of molten Al2O3(l). The half-reactions that occur are C(s) + 2 O2-(aq) CO2(g) + 4 e-

Al3+(l) + 3 e- Al(s)The mass of Al(l) produced for each 1.00 kg of C(s) consumed is

a. 1.69 kgb. 2.45 kgc. 3.00 kgd. 6.00 kg


A particular voltaic cell is represented by

Ag(s)Ag+(aq)Cr2O72-(aq), Cr3+(aq), H+(aq)C(s)

____ 105. The net ionic equation for this voltaic cell is

a. 6 Ag(s) + Cr2O72-(aq) + 14 H+(aq) 6 Ag+(aq) + 2 Cr3+(aq) + 7 H2O(l)

b. 6 Ag+(aq) + Cr2O72-(aq) + 14 H+(aq) 6 Ag(s) + 2 Cr3+(aq) + 7 H2O(l)

c. Ag+(aq) + Cr2O72-(aq) + 14 H+(aq) Ag(s) + 2 Cr3+(aq) + 7 H2O(l)

d. Ag(s) + Cr2O72-(aq) + 14 H+(aq) Ag+(aq) + 2 Cr3+(aq) + 7 H2O(l)


Voltaic cells are used as portable sources of electrical energy. One common cell is the rechargeable nickel-cadmium cell.

The equation representing the discharge of this cell is

NiO2(s) + Cd(s) + 2 H2O(l) Cd(OH)2(s) + Ni(OH)2(s)

____ 106. The oxidation half-reaction for the discharge of this cell is

a. Cd(s) + 2 OH-(aq) Cd(OH)2(s) + 2 e-

b. NiO2(s) + 2 H2O(l) + 2 e- Ni(OH)2(s) + 2 OH-(aq)c. NiO2(s) + 2 H2O(l)Ni(OH)2(s) + 2 OH-(aq) + 2 e-

d. Cd(s) + 2 OH-(aq) + 2 e- Cd(OH)2(s)

____ 107. In this system, the strongest oxidizing agent is

a. NiO2(s)b. Cd(s)c. Cd(OH)2(s)d. H2O(l)


Voltaic Cell

In this apparatus, the anions in the solution move from the hydrogen half-cell solution into the salt bridge and migrate toward the X(s) electrode.

____ 108. As this cell operates, electrons flow from

a. X(s) to the inert electrode and the pH in the hydrogen half-cell increasesb. X(s) to the inert electrode and the pH in the hydrogen half-cell decreasesc. the inert electrode to X(s) and the pH in the hydrogen half-cell increasesd. the inert electrode to X(s) and the pH in the hydrogen half-cell decreases

____ 109. If the voltmeter reads +0.45 V under standard conditions, then X(s) is most likely

a. Ni(s)b. Fe(s)c. Zn(s)d. Mg(s)


Solid-state lithium batteries are being developed as miniature, rechargeable energy sources. Different sizes and shapes of batteries are possible becasue the electrolyte is a very thin polymer layer. A simplified diagram of the battery is drawn below.

Relevant EquationsLi(s) Li+(s) + e-

FeS2(s) + e- FeS2-(s)

____ 110. If the net cell potential of a solid-state lithium battery is +3.00 V, the the reduction potential for the half-reaction FeS2(s) + e- FeS2

-(s) is

a. +6.04 Vb. +3.04 Vc. - 0.04 Vd. - 6.04 V

____ 111. The strongest reducing agent in the solid-state lithium battery is

a. Li(s)b. Li+(s)c. FeS2(s)d. FeS2

-(s)

____ 112. During the operation of the solid-state lithium battery,

a. FeS2-(s) ions migrate toward the strongest oxidizing agent in the system

b. FeS2-(s) ions migrate toward the FeS2(s) electrode

c. lithium ions migrate toward the lithium electroded. lithium ions migrate toward the cathode


Iron objects will readily corrode when exposed to air and moisture, as represented by the following equation.

O2(g) + 2 H2O(l) + 2 Fe(s) 2 Fe2+(aq) + 4 OH-(aq)

____ 113. Which of the following metals can be attached to an iron object to prevent corrosion of the iron?

a. Copperb. Nickelc. Leadd. Zinc


Electrochemical Cell

The diagram above provides a representation of the process of electrolysis.

____ 114. Which of the following statements describes what happens during the operation of this cell?

a. Chemical energy is converted to electrical energy.b. Electrical energy is converted to chemical energy.c. Electrons flow toward the anode.d. Plating takes place at the anode.

____ 115. A solution containing a metal ion with a 3+ charge was electrolyzed bya 5.0 A current for 10.0 min. If 1.19 g of the metal was electroplated, then the metal was likely

a. indiumb. scandiumc. aluminiumd. potassium


Some car manufacturers have designed an anticorrosion system that sends a weak electric current from the battery to the frame of the car. The current provides a source of electrons, which reduces corrosion of the steel frame.

____ 116. Which of the following methods could not be used as an alternative to the method of corrosion prevention described above?

a. Galvanize the steel frame with zinc.b. Coat the steel frame with inert plastic polymers.c. Use a paint that prevents contact of the steel frame with the environment.d. Bolt sacrificial anodes made of copper to the steel frame.


To determine the identity of an unknown metallic ion in a solution, a student designed the voltaic cell shown below.

____ 117. The student chose zinc for the anode because zinc

a. gains electrons easilyb. can be easily reducedc. is an oxidizing agentd. is a reducing agent

____ 118. If the cell generates a voltage of +1.24 V under standard conditions, the half-reaction occurring at the cathode will have an electrode potential of

a. +2.00 Vb. - 2.00 Vc. +0.48 V

d. - 0.48 V

____ 119. If the zinc anode loses 200 g of mass during the operation of the cell, then the number of moles of electrons transferred is

a. 1.53 molb. 3.06 molc. 6.12 mold. 12.2 mol


Some pacemakers use specialized lithium cells as a power source. The half-reactions and electrode potential in thise cells are

2 SOCl2(aq) + 4 e- 4 Cl-(aq) + S(s) + SO2(aq) E° = +0.36 V Li+(aq) + e- Li(s) E° = - 3.04 V

____ 120. The net ionic equation and potential of this lithium cell are

a. 2 SOCl2(aq) + Li+(aq) 4 Cl-(aq) + S(s) + SO2(aq) + Li(s) E°net = +3.40 Vb. 2 SOCl2(aq) + 4 Li+(aq) 4 Cl-(aq) + S(s) + SO2(aq) + 4 Li(s) E°net = +2.68 Vc. 2 SOCl2(aq) + Li(s) 4 Cl-(aq) + S(s) + SO2(aq) + Li+(aq) E°net = +2.68 Vd. 2 SOCl2(aq) + 4 Li(s) 4 Cl-(aq) + S(s) + SO2(aq) + 4 Li+(aq) E°net = +3.40 V


Hydrogen-oxygen fuel cells have been used for years in spacecraft and more recently in small-scale power plants to generate electricity. Now, some governments and companies are working together to perfect this type of fuel cell for automobile use, and experiments are currently being conducted with operational prototypes. A diagram of a hydrogen-oxygen fuel cell is shown below.

____ 121. From an ecological perspective, a reason why hydrogen-oxygen fuel cells should not be used to power automobiles is that

a. hydrogen fuel can be produced through the electrolysis is seawater by using the energy produced from burning fossil fuels

b. cars powered by a hydrogen-oxygen fuel cell would be up to 30% more efficient than cars powered by gasoline

c. water vapour is the primary byproduct of the celld. oxygen is readily available from the atmosphere


Copper can be refined (purified) using an apparatus like the one shown below, which is a small-scale version of an industrial apparatus.

____ 122. In this electrochemical cell, the purified copper sheet acts as the

a. anode and is the site where SO42-(aq) ions are oxidized

b. cathode and is the site where SO42-(aq) ions are reduced

c. anode and is the site where Cu2+(aq) ions are oxidizedd. cathode and is the site where Cu2+(aq) ions are reduced


The silver oxide alkaline cell is a minature power source used in watches, calculators, hearing aids, and cameras. The construction of this cell is shown in the following diagram.

Half-Reactions Zn(OH)2(s) + 2 e- Zn(s) + 2 OH-(aq) E° = - 1.25 V Ag2O(s) + H2O(l) + 2 e- 2 Ag(s) + 2 OH-(aq) E° = +0.34 V

____ 123. During the discharge of this cell, the substance oxidized is

a. Zn(s)b. Ag(s)c. H2O(l)d. Ag2O(s)

____ 124. In this cell, the separator must be porous in order to

a. allow migration of ionsb. replenish the electrolyec. provide a pathway for electron flowd. provide a surface on which electron transfer can occur

____ 125. Using lowest whole number coefficients, the coefficient for H2O(l) in the balanced net cell equation for the reaction that occurs during the discharge of the cell is

a. 1b. 2c. 3d. 4

____ 126. As the cell operates, the

a. [OH-(aq)] increasesb. mass of Zn(s) increasesc. mass of Ag2O(s) decreasesd. mass of Zn(OH)2(s) decreases

Use the following diagram to answer the next question.


____ 127. The cell in the diagram was constructed and connected by a chemistry student. The voltage of the cell remained at 0.00 V trial after trial. One possible reason for the malfunction of the cell was that the

a. concentration of the solutions were too lowb. solution in the U-tube was a non-electrolytec. redox reaction was non-spontaneousd. voltmeter was connected backward


In the late 1980s, the Canadian dollar bill was replaced by a coin commonly called the “loonie.” The loonie is manufactured from nickel discks that are stamped and then coated with a thin laye of copper (87.5%) and tin (12.5%) to provide the shiny gold-coloured appearence. This layer is applied through an electrolysis process in which the stamped loone is one of the electrodes and copper metal is the other electrode.

____ 128. If the plating of the loonie occurs in a Sn2+(aq) and Cu2+(aq) solution, the the reaction that occurs at the cathode is

a. 2 H2O(l) + 2 e- H2(g) + 2 OH-(aq)b. 2 H2O(l) O2(g) + 4 H+(aq) + 4 e-

c. Cu2+(aq) + 2 e- Cu(s)d. Cu(s) Cu2+(aq) + 2 e-


Concern about increased air pollution and the increasing use of non-renewable resources has accelerated research into alternatives to the internal combustion engine. One alternative is a battery-powered electric motor. Several “new” efficient batteries are being tested. The diagram below represents one of these batteries.

Aluminium-Air Battery

____ 129. In this aluminium-air battery, the O2(g) acts as the

a. reducing agent and gains electronsb. reducing agent and loses electronsc. oxidizing agent and gains electronsd. oxidizing agent and loses electrons

____ 130. The reduction half-reaction for this aluminium-air battery is

a. 2 H2O(l) + 2 e- H2(g) + 2 OH-(aq)b. Na+(aq) + e- Na(s)c. O2(g) + 4 H+(aq) + 4 e- 2 H2O(l)d. O2(g) + 2 H2O(l) + 4 e- 4 OH-(aq)

____ 131. The standard voltage produced by this aluminium-air cell is

a. +2.36 Vb. +2.06 Vc. +0.83 Vd. - 1.05 V


A chemistry student constructs the cell shown below.

____ 132. The net equation and the predicted voltage for the operating cell are

a. MnO4-(aq) + 8 H+(aq) + Cu(s) Mn2+(aq) + 4 H2O(l) + Cu2+(aq) E°net = +1.17 V

b. MnO4-(aq) + 8 H+(aq) + Cu(s) Mn2+(aq) + 4 H2O(l) + Cu2+(aq) E°net = +1.85 V

c. MnO4-(aq) + 16 H+(aq) + 5 Cu(s) Mn2+(aq) + 8 H2O(l) + 5 Cu2+(aq) E°net = +1.17 V

d. MnO4-(aq) + 16 H+(aq) + 5 Cu(s) Mn2+(aq) + 8 H2O(l) + 5 Cu2+(aq) E°net = +1.85 V

____ 133. During the operation of this cell,

a. electrons flow from the copper electrode to the carbon electrodeb. cations migrate toward the copper electrodec. anions migrate toward the carbon electroded. the concentration of the sulfate ions decreases

____ 134. Which of the following statements does not apply to the operation of this cell?

a. The oxidation state of the reducing agent changes from 0 to +2.b. MnO4

-(aq) is reduced at the carbon cathode.c. Cu(s) is oxidized at the anode.d. MnO4

-(aq) loses electrons.

____ 135. The voltage of an electrochemical cell is +0.20 V. If one of the half-reactions is the reduction of Cu2+(aq), then the other half-reaction that occus could be

a. 2 I-(aq) I2(s) + 2 e-

b. S(s) + 2 H+(aq) + 2 e- H2S(aq)c. H2S(aq) S(s) + 2 H+(aq) + 2 e-

d. I2(s) + 2 e- 2 I-(aq)

____ 136. Sacrificial metals may be used to protect pipelines, septic tanks, and ship propellers. A metal that could be used as a sacrificial anode to protect iron is

a. magnesiumb. tinc. leadd. silver

____ 137. Electrolysis of MgCl2(aq) will not produce magnesium metal because ___i___ is a stronger ___ii___ agent than Mg2+(aq).


i iiA Cl-(aq) oxidizingB H2O(l) reducingC H2O(l) oxidizingD Cl-(aq) reducing

a. b. c. d.

____ 138. If the Cu2+(aq) / Cu(s) reduction half-reaction was assigned a reduction potential value of 0.00 V for an electrode potential table, then the Ni2+(aq) / Ni(s) half-reaction on that table would have a reduction potential value of

a. +0.26 Vb. +0.08 Vc. - 0.26 Vd. - 0.60 V



____ 139. For this cell, the potential is

a. +1.10 Vb. +0.42 Vc. - 0.42 Vd. - 1.10 V


Chromium plating of objects, such as iron car bumpers, to prevent corrosion actually involves the plating of three different meals in three separate electolyic cells. The first cell contains a solution of a copper salt, the second a solution of nickel salt, and the third a solution of chromium salt.

____ 140. During the nickel stage of of the electroplating process, the nickel(II) ions ___i___ electrons, and the metal is deposited on the ___ii___.


i iiA gain anodeB gain cathodeC lose anodeD lose anode

a. b. c. d.

Use the following information to answer the next 3 questions.

Restorers of antique cars often refinish chrome-plated parts by electroplating them.The par is attached to one electrode of an electrolytic cell in which the other electrode is

lead. The electrolyte is a solution of dichomic acid, H2Cr2O7(aq).

____ 141. The plating of chromium metal will take place at the

a. anode where oxidation occursb. anode where reduction occursc. cathode where oxidation occursd. cathode where reduction occurs

____ 142. During the operation of this cell,

a. Pb(s) is reducedb. H2Cr2O7(aq) is oxidizedc. the pH of the solution increasesd. the total energy of the system decreases

____ 143. A metal that will react spontaneously with Cr3+(aq) in a chromium-plating solution is

a. aluminiumb. cadmiumc. leadd. tin

____ 144. If the electrochemical cell Cd(s) Cd2+(aq) Ag+(aq) Ag(s) produces a 6.00 A current for 2.00 h, the mass change of the anode will be

a. 25.2 g decreaseb. 2.25 g increasec. 48.3 g decreased. 48.3 g increase

____ 145. “Tin” cans used to store food are made from steel electroplated with a thin layer of tin. The standard reduction potential for the reduction of Sn2+(aq) ions for this process is

a. - 0.15 Vb. - 0.14 Vc. +0.14 Vd. +0.15 V

____ 146. In an experiment, a student compares several electrochemical cells. Each cell contains two metal strips in their metallic ion solutions. A voltmeter is connected by a wire between the metal strips, and a salt bridge connects the solutions. The dependent (responding) variable is the

a. voltageb. concentration of the solutionc. reaction of the metal and metallic iond. metal and metallic ion solution selected


____ 147. Given that the reading on the voltmeter for this cell is +1.74 V, which of the following statements is correct?

a. The reduction potential of Q2+(aq) is +2.50 V.b. Zn(s) is a weaker reducing agent than Q(s).c. Q2+(aq) would react spontaneously with Cu(s).d. Q2+(aq) is a stronger oxidizing agent than Zn2+(aq).

____ 148. An electrolytic cell differs from a voltaic cell in that the electrolytic cell

a. is spontaneousb. consumes electricityc. has an anode and a cathoded. has a positive E°net value

____ 149. If the lithium reduction half-reaction, Li+(aq) + e- Li(s), had been assigned an E° value of 0.00 V, the predicted E°net value for the reaction Cu(s) + Zn2+(aq) Cu2+(aq) + Zn(s) would be

a. +3.38 Vb. - 2.28 Vc. - 0.42 Vd. - 1.10 V


In 1936, an object of unknown purpose was discovered near Baghdad. The object was determined to be approximately 2 000 years old. This object had several similarities to modern dry cells, and as a result, was named the “Battery of Baghdad.”

It is possible, using materials known to be available 2 000 years ago, to construct a model cell that produces a voltage.

The reaction that occurs in this model cell is

Fe(s) + OC6H4O(aq) + 2 H+(aq) HOC6H4OH(aq) + Fe2+(aq) E°net = +1.25 V

____ 150. The oxidizing agent in the model cell is

a. Fe(s)b. Fe2+(aq)c. OC6H4O(aq)d. HOC6H4OH(aq)

____ 151. The substance acting as the “salt bridge” in the model cell is

a. ironb. clayc. bronze

d. asphalt/straw

____ 152. As the model cell operates, one would predict that the quinone/vinegar solution would

a. remain unchangedb. become less acidicc. become less basicd. decrease in pH

____ 153. The predicted E° under standard conditions for the quinone/vinegar solution half-reaction, OC6H4O(aq) + 2 H+(aq) + 2 e- HOC6H4OH(aq), is

a. +0.80 Vb. +1.70 Vc. - 0.80 Vd. - 1.70 V

Use the following information to answer the next two questions.

This simplified diagram shows the cell used in the Chlor-Alkali process at the Dow Chemical Plant in Fort Saskatchewan, Alberta.

____ 154. The cell shown in the diagram is

a. electrolyticb. voltaicc. galvanicd. acid-base

____ 155. Products I, II, and III from this cell, respectively, are

a. Cl2(g), H2(g), and HCl(aq)

b. H2(g), Cl2(g), and NaOH(aq)c. HCl(g), Cl2(g), and NaOH(aq)d. Cl2(g), H2(g), and NaOH(aq)


The chlor-alkali process used by Dow Chemical in Fort Saskatchewan uses sodium chloride from underground deposits. The sodium chloride is dissolved in water and then pumped into electrolytic cells where a current is passed through the solution to form yellow chlorine gas, colourless hydrogen gas, and aqueous sodium hydroxide.The net ionic equaiton is

2 H2O(l) + Cl-(aq) Cl2(g) + 2 OH-(aq) + H2(g)

____ 156. In the electrolysis of NaCl(aq), the cathode half-reaction is

a. Na+(aq) + e- Na(s)b. 2 Cl-(aq) Cl2(g) + 2 e-

c. 2 H2O(l) O2(g) + 4 H+(aq) + 4 e-

d. 2 H2O(l) + 2e- H2(g) + 2 OH-(aq)

____ 157. When the electric current is switched off, the

a. pH stops decreasingb. concentration of the Na+(aq) stops changingc. concentration of the Cl-(aq) stops decreasingd. concentration of the H2O(l) stops decreasing

____ 158. It is estimated that up to 25% of the iron produced annually in North America is used to replace iron objects that have been damaged by rust. The corroded iron is oftern expensive or difficult to replace and is often disposed of in landfills. Corrosion is a concern from both

a. a political and a scientific perspectiveb. an ecological and an ethical perspectivec. a technological and a scientific perspectived. an economic and an ecological perspective

____ 159. Which of the following characteristics is associated with a voltaic cell consisting of standard half-cells of nickel and zinc?

a. The E°net is +1.02 V.b. Cations migrate to the zinc electrode.c. Oxidation occurs at the nickel electrode.d. The net ionic equation is Ni2+(aq) + Zn(s) Ni(s) + Zn2+(aq)

____ 160. A student constructed a standard electrochemical cell by using copper metal and a copper(II) nitrate solution in one half-cell and an unlabelled metal and a nitrate solution of the metal ion in the other half-cell. The two half-cells were connected by a voltmeter, which then registered +0.79 V. If the copper electrode was the cathode, then the unlabelled metal electrode was likely

a. tinb. ironc. silverd. chromium


A student set up the following electrochemical cell and allowed it to operate for afew minutes.

____ 161. The gas formed near electrode 2 is most likely

a. I2(g)b. Na(g)c. O2(g)d. H2(g)

Use the following information to answer the next two questions.

In order to refinish a car bumper, the first step is to clean the bumper and repair any damaged areas. The second step is the electroplating of nickel on the bumper as shown below.

____ 162. The reaction that would occur at the anode in the electroplating cell above is

a. Ni(s) Ni2+(aq) + 2 e-

b. Ni2+(aq) + 2 e- Ni(s)c. Cu(s) Cu2+(aq) + 2 e-

d. SO42-(aq) + H2O(l) + 2 e- SO3

2-(aq) + 2 OH-(aq)

____ 163. In the third step of the electroplating process, the bumper is transferred to a tank that contains CrSO4(aq). A current of 3 750 A is used to plate a thin layer of chromium over the nickel. If the mass of the chromium layer is 125 g, then the time required for this plating process to occur is

a. 0.515 minb. 1.03 minc. 2.06 mind. 124 min

Numeric Response

164. The oxidation numbers of sulfur in SO2(g), SO3(g), H2SO3(aq), and H2SO4(aq), respectively, are __, __, __, __.

(Record your four digit answer in the numeric response section.)

165. Using the Table of Standard Electrode Potentials, the numbered oxidizing agents listed from strongest to weakest are __, __, __, __.

1 Sn2+(aq)2 Cu2+(aq)3 Zn2+(aq)4 Pb2+(aq)

(Record your four digit answer in the numerical response section.)


__NH3(g) + __O2(g) __NO2(g) + __H2O(g)

166. When balanced in terms of lowest whole numbers, the coefficients for this equation are, repectively, __, __, __, and __.



A student titrated samples of sulfurous acid with a potassium permanganate solution. He obtained the following results:

Table 1. Volumes of 0.0310 mol/L KMnO4(aq) required to completely react with 100.0 mL samples of sulfurous acid.

Trial 1 2 3 4 Final buret reading (mL) 9.50 18.15 26.75 34.75 Initial buret reading (mL) 1.00 9.50 18.15 26.75 Final colour of mixture pink pink pink colourless

167. To determine the concentration of sulfurous acid, the average volume of potassium permanganate use is ________ mL.

(Record your three digit answer in the numeric response section.)

168. The concentration of sulfurous acid in the sample is _____ mmol/L.


169. When the redox reaction

__H2O(l) + __NO2-(aq) + __Al(s) __NH3(g) + __AlO2

-(aq) + __H+(aq)

is balanced using lowest whole number cofficients, the coefficient of

H2O(l) is _______ (Record in the first column)NO2

-(aq) is _____ (Record in the second column)Al(s) is _________ (Record in the third column)H+(aq) is _______ (Record in the fourth column)

(Record your four digit response in the numeric response section.)


ICCP (Impressed Current Cathodic Protection) is a corrosion prevention technique that is used to protect buried metal structures. A low-voltage current (electron flow) is applied to the buried metal structure such that only reduction reactions can occur at its surface.

170. The ground water surrounding the buried metal structure may contain the following ions.

1 Pb2+(aq) 2 Fe2+(aq) 3 Fe3+(aq) 4 Cd2+(aq)

The order in which these ions are reduced on the surface of the metal structure is __, __, __ and __.

(Record your three digit number in the numeric response section.)


1 Fe2+(aq) + Cr3+(aq) Fe3+(aq) + Cr2+(aq) 2 NH3(aq) + H2O(l) NH4

+(aq) + OH-(aq)

3 2 NH3(g) + O2(g) 2 NO2(g) + 3 H2O(g) 4 Mg2+(aq) + 2 OH-(aq) Mg(OH)2(s) 5 Sn2+(aq) + 2 NO3

-(aq) + 4 H+(aq) Sn4+(aq) + 2 NO2(g) + 2 H2O(l) 6 PbSO4(s) + SO3

2-(aq) + 2 OH-(aq) H2O(l) + Pb(s) + 2 SO42-(aq)

171. The equations that represent oxidation-reduction reactions, listed in any order, are __, __, __, and __.



Titration of 20.0 mL Samples of Acidified H2O2(l)with 0.15 mL KMnO4(aq)

Trial I II III IV Final Buret volume (mL) 18.3 34.6 17.4 33.8 Initial Buret volume (mL) 0.4 18.3 0.9 17.4 Colour at endpoint purple pink pink pink

172. The volume of potassium permanganate that should be used in subsequent calculations is ________ mL.


173. The hydrogen peroxide concentration is _______ mol/L.



To determine the concentration of Sn2+(aq) solution, a student titrated a 50.00 mL sample of acidified Sn2+(aq) with 1.44 mmol/L KMnO4(aq). The titration required 24.83 mL of KMnO4(aq) in order to reach a pale pink endpoint.

174. The concentration of Sn2+(aq) in the sample is _______ mmol/L.



The beautiful patterns of butterfly wings, the stripes on zebra pelts and the myriad of colours of tropical fish all result froom oscillating chemical reactions. These chemcial reactions can be studied in a much simpler form in the laboratory. In 1958, the Russian chemist B.P. Belousoz discovered a complet reaction sequence in which the concentration of reactants and products oscillated over time.

Unbalanced Reaction Equations I __H+(aq) + __BrO2

-(aq) + __ BrO3-(aq) __BrO2(aq) + __H2O(l)

II __Ce3+(aq) + __BrO2(aq) Ce4+(aq) + __BrO2-(aq)

III __BrO2-(aq) __BrO3

-(aq) + __BrO-(aq)

175. When reaction equation I is balanced with lowest whole number coefficients, the coefficient of

H+(aq) is ___________ (Record in the first column)BrO2

-(aq) is ___________ (Record in the second column)BrO3

-(aq) is ___________ (Record in the third column)BrO2(aq) is ___________ (Record in the fourth column)



A 0.532 mol/L solution of Ce4+(aq) was used to titrate a25.0 mL sample of Sn2+(aq).

Volume UsedFinal Buret reading (mL) 43.5

Initial Buret reading (mL) 12.6

The half-reaction for cerium(IV) can be represented byCe4+(aq) + e- Ce3+(aq) E° = +1.61 V

176. The [Sn2+(aq)] of the sample, expressed in scientific notation, is _______ x 10-1 mol/L.



At one time, an aqueous solution of formaldehyde called formalin(CH2O(aq)) was used as a disinfectant and as a tissue preservative. Today, formalin is commonly used in the industrial preparation of plastics and resins.

Formalin can be produced by reacting methanol with acidified potassium dichromate, as represented by the following unbalanced equation.

__CH3OH(l) + __Cr2O72-(aq) __H+(aq) CH2O(aq) + __Cr3+(aq) + __H2O(l)

177. When 39.5 kg of methanol is reacted, the mass of formalin produced is _______ kg.



An acidic solution of nickel(II) nitrate is poured into a tin container.

Chemical Changes

1 does not react 2 is oxidized 3 is reduced 4 reacts but there is no change in its oxidation number

178. Match each of the chemical changes listed above with the reaction species given below.

tin __________ (Record in first column)nitrate ion __________ (Record in second column)nickel(II) ion __________ (Record in third column)hydrogen ion __________ (Record in fourth column)


Use the following equations to answer the next question.

1 HSO3-(aq) + HCO3

-(aq) H2CO3(aq) + SO32-(aq)

2 C6H12O6(aq) + 6 O2(g) 6 CO2(g) + 6 H2O(l)3 Ni2+(aq) + Fe(s) Fe2+(aq) + Ni(s)4 Co2+(aq) + 2 Fe2+(aq) 2 Fe3+(aq) + Co(s)5 6 CO2(g) + 6 H2O(l) C6H12O6(aq) + 6 O2(g)

179. Match the equations, as numbered above, with the corresponding decription below.

A biological redox reaction carried outin a plant cell but not in an animal cell _____ (Record in the first column)

A biological redox reaction carried outin both animal and plant cells _____ (Record in the second column)

A spontaneous, non-biological redoxreaction _____ (Record in the third column)

A non-spontaneous, non-biologicalredox reaction _____ (Record in the fourth column)


180. When the equation V2O5(s) + Mn(s) VO(s) + MnO2(s) is balanced using the lowest whole number coefficients, the coefficient of

V2O5(s) is _________ (Record in the first column)Mn(s) is _________ (Record in the second column)VO(s) is _________ (Record in the third column)MnO2(s) is _________ (Record in the fourth column)


181. Nitrogen forms a number of oxides. Examples include NO(g), NO2(g), N2O(g), and N2O5(g). The oxidation of number of nitrogen in each compound listed above is, respectively, ___, ___, ___, and ___.

(Record your four digit number in the numeric response section).


A student dipped 12.50 g strips of four different metals, Ag(s), Cu(s), Pb(s), and Mg(s), into a beaker containing 250 mL of 1.00 mol/L HCl(aq) in order to determine an activity series. One of the metals reacted immediately and vigorously with the acid.

182. The mass of metal that reacted with the hydrochloric acid is _______g.


183. The volume of 0.160 mol/L K2Cr2O2(aq) required to completely react with 10.0 mL of acidic 0.0881 mol/L H2O2(aq) is _____ mL.


184. The oxidation numbers of carbon in HCOOH(aq), C6H12O6(s), CO2(g), and CHCl3(g), respectively, are ___, ___, ___, and ___.


185. When 1.20 mol of H2PO4-(aq) react according to the equation

12 H2PO4-(aq) + 12 H+(aq) + 10 Br-(aq) 3 P4(s) + 18 H2O(l) + 10 BrO3

-(aq),

the number of moles of electrons transferred is ______ mol.



A thermite reaction is a highly exothermic process that is used in welding massive objects such as ship propellers and train rails. The reaction can be represented by the equation

2 Al(s) + Fe2O3(s) Al2O3(s) + Fe(l)

186. The value of the oxidation number for

aluminium in Al(s) is _____ (Record in the first column) iron in Fe2O3(s) is _____ (Record in the second column) aluminium in Al2O3(s) is _____ (Record in the third column) iron in Fe(l) is _____ (Record in the fourth column)


Use the following information to answser the next question.

Four Reaction Equations

In(s) + La3+(aq) no reactionNp(s) + La3+(aq) Np3+(aq) + La(s)Np(s) + Nd3+(aq) Np3+(aq) + Nd(s)

La(s) + Nd3+(aq) no reaction

Key

1 In(s) 5 In3+(aq)2 Np(s) 6 Np3+(aq)3 Nd(s) 7 Nd3+(aq)4 La(s) 8 La3+(aq)

187. Arranged in order form strongest to weakest, the oxidizing agents above are _____, _____, _____, and _____.


188. In a standard aluminium-silver cell,the mass of the anode decreases by 0.270 g. The increase in the mass of the cathode is ________g.

(Record your three digit response in the numerical response section.)


Cell I E°net = +1.33 V anode: Ni(s) Ni2+(aq) + 2 e-

cathode: X2(s) + 2 e- 2 X-(aq)

Cell II E°net = +0.23 V anode: A(s) A2+(aq) + 2 e-

cathode: Ni2+(aq) + 2 e- Ni(s)

189. The predicted cell potential for the spontaneous reaction that occurs by combining the half-cells X2(s)|X-(aq) and A(s)|A2+(aq) is _____ V.



Corrosion of iron causes billions of dollars in damage every year. A reaction that occurs during corrosion is

4 Fe(s) + 3 O2(g) + 6 H2O(l) 4 Fe(OH)3(s) + energy

190. If 6.98 g of iron corroded, then the volume of oxygen gas consumed at SATP is _________ L. (Note: 1 mol of oxygen at SATP occupies 24.8 L)


191. In an electrolytic cell, 61.0 g of Zn(s) was plated in 10.0 min. The mass of Cr(s) that could be plated in the same time using the same current from a solution of Cr3+(aq) is _________ g.



The diagram represents the voltaic cell

Ni(s)|Ni2+(aq)||MnO4 (aq), Mn2+(aq), H+(aq)|C(s)

192. The nickel electrode is represented by number ___ (Record in first column)

The acidic MnO4 (aq) solution is repesented bynumber ___ (Record in second column)

The cation migration is represented by number ___ (Record in third column)

The cathode is represented by number ___ (Record in fourth column)



Reagents

1 Ag(s) 5 1.0 mol/L Fe2+(aq) 2 Cd(s) 6 1.0 mol/L Hg2+(aq) 3 Hg(l) 7 1.0 mol/L Cd2+(aq) 4 Fe(s) 8 1.0 mol/L Ag+(aq)

193. What reagents are required in order for the cell to produce a voltage of 1.25 V?

Electrode I ________ (Record in first column) Solution II ________ (Record in second column) Electrode III ________ (Record in third column) Solution IV ________ (Record in fourth column)

(Record your four digit answer in the numeric response secetion.)

194. Under standard conditions, hydrogen gas reacts with Au3+(aq) ions to produce Au(s). The net cell potential for the reaction is +/- ___ V.



The sodium metal in television picture tubes reacts with oxygen that would otherwise oxidize the tungsten and phosphorus found in the tubes. Tungsten and phosphorus are vital to the function of the picture tubes.

195. The mass of sodium that will react when 0.350 mol of electrons is transferred is ________ g.



An Electrochemical Cell

196. A student attempted to replicate a traditional Daniell Cell by setting up the electrochemical cell shown above. Under standard conditions, the electrical potential of the cell should be +/- _______V.



Voltaic Cell

197. In the diagram above, the number that represents the

anode is __________ (Record in the first column)cathode is __________ (Record in the second column)cation flow is __________ (Record in the third column)electron flow is __________ (Record in the fourth column)



In vehicles, hydrogen fuel cells are about twice as efficient as

gasoline engines. One method used to produce the hydrogen for the fuel cell is the electrolysis of water, as represented by the diagram below.

Electrolysis of Water

198. Match four of the numbers in the diagram above with their appropriate labels given below

The direction of cation flow _____ (Record in the first column)The direction of electron flow _____ (Record in the second column)The site where oxidation occurs _____ (Record in the third column)The site where electrons are gained _____ (Record in the fourth column)



Solid-state lithium batteries are being developed as miniature, rechargeable energy sources. Different sizes and shapes of batteries are possible becasue the electrolyte is a very thin polymer layer. A simplified diagram of the battery is drawn below.

Relevant EquationsLi(s) Li+(s) + e-

FeS2(s) + e- FeS2-(s)

199. If a solid-state lithium battery produced 5.00 mA in 8.25 h, then the mass of lithium consumed would be _______ mg.



A voltaic cell capable of lighting a small light bulb can be made by placing copper and zinc strips in a lemon.

200. Identify the part of the voltaic cell, as numbered above, that corresponds to each of the descriptors listed below.

Anode ___________ (Record in the first column)Cathode ___________ (Record in the second column)Electron flow ___________ (Record in the third column)Electrolyte ___________ (Record in the fourth column)



To determine the identity of an unknown metallic ion in a solution, a student designed the voltaic cell shown below.

201. If the charge on the unidentified metal ion is 3+, then the number of moles of the metal produced when the zinc anode decreases in mass by 200 g is _______ mol.



Hydrogen-oxygen fuel cells have been used for years in spacecraft and more recently in small-scale power plants to generate electricity. Now, some governments and companies are working together to perfect this type of fuel cell for automobile use, and experiments are currently being conducted with operational prototypes. A diagram of a hydrogen-oxygen fuel cell is shown below.

202. In the diagram above, the anode, the cathode, the electrolyte, and a product of the reaction are labelled, respectively, __, __, __, and __.



Copper can be refined (purified) using an apparatus like the one shown below, which is a small-scale version of an industrial apparatus.

203. If the direct current power supply produces a steady 3.50 A current, then the time required to deposit 0.100 g of purified copper is _______ s.



The silver oxide alkaline cell is a minature power source used in watches, calculators, hearing aids, and cameras. The construction of this cell is shown in the following diagram.

Half-Reactions Zn(OH)2(s) + 2 e- Zn(s) + 2 OH-(aq) E° = - 1.25 V Ag2O(s) + H2O(l) + 2 e- 2 Ag(s) + 2 OH-(aq) E° = +0.34 V

204. During discharge, the voltage generated by the cell is +/- _____ V.


205. The voltage generated by three silver oxide cells connected in series is _______ V.

(Record your three digit response in the numeric response section.)


Concern about increased air pollution and the increasing use of non-renewable resources has accelerated research into alternatives to the internal combustion engine. One alternative is a battery-powered electric motor. Several “new” efficient batteries are being tested. The diagram below represents one of these batteries.

Aluminium-Air Battery

206. When three aluminium-air cells are connected in series, the net voltage generated by the battery +/- ________ V.



2 RhCl63-(aq) + 3 Zn(s) 3 Zn2+(aq) + 2 Rh(s) + 12 Cl-(aq) E°net = +1.20 V

207. The standard electrode potential for the half-reaction

RhCl63-(aq) + 3 e- Rh(s) + 6 Cl-(aq) is _______ V.



A chemistry student constructs the cell shown below.

208. During the operation of this cell, if 0.354 mol of MnO4-(aq) were consumed, then the mass of the copper

electrode would decrease by _______ g.



Chromium plating of objects, such as iron car bumpers, to prevent corrosion actually involves the plating of three different meals in three separate electolyic cells. The first cell contains a solution of a copper salt, the second a solution of nickel salt, and the third a solution of chromium salt.

209.Use the following additional information to answer the next question.

Electroplating Cell

Use the numbers that identify the parts of the electroplating cell in the diagram above to complete the statements belwo.

The cathode is identified by ____ (Record in the first column)The electron movement is identified by ____ (Record in the second column)The cation movement is identified by ____ (Record in the third column)The anion is identified by ____ (Record in the fourth column)


210. A chromium electroplating cell needs to operate at a current of 2000 A to plate 112 g of chromium onto a car bumper. In order to plate the bumper, the cell must operate for ___________min.



During the operation of a NiCad battery, the two half-reactions that occur are

I Cd(s) + 2 OH-(aq) Cd(OH)2(s) + 2 e- E° = ? V II NiO2(s) + 2 H2O(l) + 2 e- Ni(OH)2(s) + 2 OH-(aq) E° = -0.49 V

211. On discharging, the electric potential of a NiCad battery is +1.40 V. The reduction potential for half-reaction I is - ________ V.



212. Identify the part of the electrochemical cell, as numbered above, that correponds to the term listed below.

Cathode _____ (Record in the first column)External electron circuit _____ (Record in the second column)Oxidizing agent _____ (Record in the third column)Anode _____ (Record in the fourth column)



In 1936, an object of unknown purpose was discovered near Baghdad. The object was determined to be approximately 2 000 years old. This object had several similarities to modern dry cells, and as a result, was named the “Battery of Baghdad.”

It is possible, using materials known to be available 2 000 years ago, to construct a model cell that produces a voltage.

The reaction that occurs in this model cell is

Fe(s) + OC6H4O(aq) + 2 H+(aq) HOC6H4OH(aq) + Fe2+(aq) E°net = +1.25 V

213. The time in hours that the model cell would have to operate at 10.0 A to consume 35.0 g of Fe(s) is ____________h.



The chlor-alkali process used by Dow Chemical in Fort Saskatchewan uses sodium chloride from underground deposits. The sodium chloride is dissolved in water and then pumped into electrolytic cells where a current is passed through the solution to form yellow chlorine gas, colourless hydrogen gas, and aqueous sodium hydroxide.The net ionic equaiton is

2 H2O(l) + Cl-(aq) Cl2(g) + 2 OH-(aq) + H2(g)

214. If the mass of the element formed at the anode is 78.1 g, the mass of element formed at the cathode is _________ g.


Use the following equation to answer the next question.

Sn4+(aq) + 2 Cr2+(aq) Sn2+(aq) + 2 Cr3+(aq)

215. At standard conditions, the net potential for the reaction represented by the equation above is ________V.



Voltaic Cell

216. In the diagram above, the number that represents the

anode is _____ (Record in the first column) cathode is _____ (Record in the second column) cation flow is _____ (Record in the third column) electron flow is _____ (Record in the fourth column)


Short Answer

217.Use the following information to answer the next question.

Before fleeing Denmark in 1943, Niels Bohr prevented two Nobel prize gold medals from being seized by German authorities. The gold was reacted with aqua regia (a combination of concentrated nitric acid and hydrochloric acid). The unbalanced equation for the reaction that Bohr used is

Au(s) + H+(aq) + NO3-(aq) + Cl-(aq) AuCl4

-(aq) + NO2(g) + H2O(l)

After the Second World War, the gold was recovered, and then the medals were recast.

1a. Balance the equation above using oxidation-reduction methods. Identify the oxidizing and reducing agents and the number of electrons lost or gained by each. (3 marks)

1b. If the initial combined mass of the gold in the medals was 225 g and the total volume of aqueous solution was 4.00 L, then what was the final concentration of AuCl4

-(aq) after the medals were completely reacted? (3 marks)

1c. The reduction potential for the AuCl4-(aq) half-reaction is 1.00V. Suggest a substance that could be

used to convert the AuCl4-(aq) back into Au(s). Justify your choice. (2 marks)

Communication (2 marks)


A student was given four solutions labelled A, B, C, and D. One contained Cl-(aq) ions, one contained Br-(aq) ions, one contained Sn2+(aq) ions, and one contained Fe2+(aq) ions.

In order to identify each solution, the student selected the following acidified reagents:

MnO4-(aq), SO4

2-(aq), NO3-(aq) and Cr2O7

2-(aq)

The student combined some of each solution with the reagents and recorded the following results:

Reagents Unknown SolutionsA B C D

H+(aq), MnO4-(aq)

H+(aq), SO42-(aq)

H+(aq), NO3-(aq)

H+(aq), Cr2O72-(aq)

If “” indicates a spontaneous reaction and “” indicates no reaction, identify what each unknown solution contained. Explain how you reached your conclusions.

219. Draw an electrolytic cell that could be used to plate an iron ring with gold.

Your answer should also include

Labels for all of the necessary parts of your cell.

The electrolyte(s) used and precise composition of the electrodes.

A balanced net cell equation and cell potential


Electroless plating has been used for many decades. Electroless plating uses a redox reaction to deposit metal on an object without the need for an electric current. Electroless platings of silver on mirrors can be prepared, under basic conditions, according to the unbalanced reaction:

CH3CHO(aq) + Ag(NH3)2OH(aq) Ag(s) + CH3COO-(aq) + H2O(l) + NH3(aq)

a. Balance the reaction equation using electrochemical methods. (3 marks)b. Identify, clearly, the reducing agent and the oxidizing agent in the electroless

silver plating reaction. (2 marks)c. Calculate the mass of silver deposited when 350 mL of a 0.250 mol/L aqueous

solution of ethanal, CH3CHO(aq), is completely consumed. (3 marks) Communication.(2 marks)

221. In the table below, the time, in hours, that each of three cells would operate four particular devices is given. The cost of each cell is also given.

Type of D CellLeClanché Zinc Chloride Alkaline

Motor Toy 1.0 h 3.0 h 11.0 hCassette Player 1.0 h 2.5 h 5.7 h

Flashlight 1.0 h 2.0 h 4.6 hPocket Radio 1.0 h 1.8 h 4.1 h

Voltage 1.5 V 1.5 V 1.5 VOperating Temperature Range 5°C - 55°C -20°C - 55°C -30°C - 55°C

Cost of Cell $0.75 $0.95 $2.25

Leclanché Cell (Zn(s)/MnO2(s))Overall Reaction2 MnO2(s) + 2 NH4Cl(aq) + Zn(s) ZnCl2•2NH3(s) + Mn2O3•H2O(s)

Zinc Chloride Cell (Zn(s)/MnO2(s))Overall Reaction8 MnO2(s) + 4 Zn(s) + ZnCl2(s) + 9 H2O(l) 8 MnOOH(s) + ZnCl2•4ZnO•5H2O(s)

Alkaline/Manganese Dioxide Cell (Zn(s)/MnO2(s))Overall Reaction2 Zn(s) + 3 MnO2(s) 2 ZnO(s) + Mn3O4(s)

a. Identify the amode common to all of the D cells. Indicate the change in oxidation number for the anode. (2 marks)

b. For how many hours could a Leclanché cell operate at 0.300 A is the limiting reagent was a 10.0 g anode? (3 marks)

c. Which type of D cell battery would you use to operate a portable cassette player outside on a mild winter day when the temperature was -12°C? Justify your choice from two different perspectives. (3 marks)


222. Describe a working voltaic cell that incorporates a standard nickel half-cell and that has a net cell potential greater than 1.00 V.

Your response should include• relevant balanced half-reaction equations and an E°net calculation• a labelled diagram• evidence that a reaction occurred in each half-cell


Several factors affect the length of time a voltaic cell can produce energy. A student has

the materials to construct several silver-zinc voltaic cells.

Design an experiment that would allow the student to test how one of these factors will affect the length of time that a silver-zinc voltaic cell can operate.

Your reposnse should include• a detailed procedure• identification of the manipulated, responding, and controlled variables• a balanced net ionic equation and E°net calculation


Electric-powered vehicles produce less air pollution than gasoline-powered vehicles. A zinc-air battery can be used in electric vehicles because it is lightweight and rechargeable. The battery uses water and oxygen gas from the air, a solid zinc electrode, and an electrolyte.

a. Write the balanced equations that represent the half-reaction that occurs at the anode and the half-reaction that occurs at the cathode of the zinc-air battery, and label which reaction occurs at the anode and which reaction occurs at the cathode. (2 marks)

b. Write the balanced net ionic equation that represents the overall reaction for the zinc-air battery anc calculate the E°net. (2 marks)

c. Determine the mass of oxygen from the air that would be required to produce a current of 1.5 x 103 A for 5.0 min. (2 marks)

d. Identify and explain a quantitative disadvantage of replacing the zinc electrode with a lead electrode. (2 marks)



In an experiment, a student constructed a standard voltaic cell using cadmium nitrate and copper(II) nitrate, as represented by the cell notation belwo.

Cd(s) Cd2+(aq) Cu2+(aq) Cu(s)

The student then measured the voltage of the cell at 25.0°C.

a. Draw and label the voltaic cell, including the anode, cathode and direction of movement of the ions and electrons. (4 marks)

b. Write the net balanced equation that represents the reaction occurring in the cell, and calculate the standard net cell potential. (2 marks)

c. Identify evidence that a reaction occurred in each half-cell. (2 marks)Communication (2 marks)


A student hypothesizes that if the concentration of copper(II) ions is increased in a copper-zinc voltaic cell, the potential difference of the cell will also increase.

Design an experiment that would allow you to test the student’s hypothesis using a copper-zinc voltaic cell.

Your response should include• a detailed procedure• a labelled diagram of the copper-zinc voltaic cell• identification of the manipulated, controlled, and responding variables


In some industrial processes sodium chromate is added to water coolants. When the coolant is drained, the chromate ions can be removed through an electrolysis process that uses an iron anode. The products of the electrolysis are aqueous iron(II) ions and solid chromium(III) hydroxide, a recoverable pollutant. The half-reaction involving the chromate ion is

CrO42-(aq) + 4 H2O(l) + 3 e- Cr(OH)3(s) + 5 OH-(aq)

a. Provide the half-reactions and a net redox reaction for this electrochemical process. (3 marks)b. A current of 3.00 A is applied for 48.0 h to a cell containing a 400 g iron anode. What is the final

mass of the iron anode? (3 marks)c. Suggest an alternative anode material that would last longer than iron. Support your answer with

relevant calculations and explanations. (2 marks)Communication (2 marks)

228. Talon Tapes of Edmonton manufactures plastic tape containing small pieces of magnesium. This tape is completely wrapped around iron pipes that will be buried underground. Explain in chemical terms the purpose(s) of each component of the tape. Your response should include relevant half-reactions.

Electrochemistry reviewAnswer Section

MULTIPLE CHOICE

1. ANS: A PTS: 1 REF: June 1992 DiplomaOBJ: 30-B1.1k TOP: oxidation KEY: definition

2. ANS: A PTS: 1 REF: June 1992 DiplomaOBJ: 30-B1.4k TOP: redox reactionKEY: identification of species undergoing reduction

3. ANS: C PTS: 1 REF: June 1992 DiplomaOBJ: 30-B1.4k TOP: electrochemistry KEY: oxidizing agents

4. ANS: B PTS: 1 REF: June 1992 DiplomaOBJ: 30-B1.7k TOP: electrochemistry KEY: predicting reactions from a table

5. ANS: B PTS: 1 REF: June 1992 DiplomaOBJ: 30-1.7k TOP: electrochemistry KEY: oxidation number

6. ANS: D PTS: 1 REF: June 1992 DiplomaOBJ: 30-B1.7k TOP: electrochemistry KEY: oxidation numbers

7. ANS: D PTS: 1 REF: June 1992 DiplomaOBJ: 30-B1.2k TOP: electrochemistry KEY: reducing agent

8. ANS: A PTS: 1 REF: June 1992 DiplomaOBJ: 30-B1.6k TOP: electrochemistry KEY: spontaneity

9. ANS: A PTS: 1 REF: June 1997 DiplomaOBJ: 30-B1.7k TOP: electrochemistry KEY: half-reactions

10. ANS: D PTS: 1 REF: June 1997 DiplomaOBJ: 30-B1.4k TOP: electrochemistry KEY: redox reactions in humans

11. ANS: A PTS: 1 REF: June 1997 DiplomaOBJ: 30-B1.7k TOP: electrochemistry KEY: balancing equations

12. ANS: B PTS: 1 REF: June 1997 DiplomaOBJ: 30-B1.7k TOP: electrochemistry KEY: balancing reactions from the table

13. ANS: D PTS: 1 REF: June 1997 DiplomaOBJ: 30-B1.8k TOP: redox titrations KEY: calculation of mass

14. ANS: A PTS: 1 REF: June 1997 DiplomaOBJ: 30-B1.2s TOP: electrochemistry KEY: redox titration

15. ANS: D PTS: 1 REF: June 1998 DiplomaOBJ: 30-B1.3k TOP: redox reactions KEY: recognizing a redox reaction

16. ANS: B PTS: 1 REF: June 1998 DiplomaOBJ: 30-B1.6k TOP: redox reactions KEY: predicting from a table

17. ANS: D PTS: 1 REF: June 1998 DiplomaOBJ: 30-B1.3s TOP: reduction tablesKEY: predicting a table based on spontaneity

18. ANS: B PTS: 1 REF: June 1998 DiplomaOBJ: 30-B1.7k TOP: redox titration KEY: predicting a reaction

19. ANS: C PTS: 1 REF: June 1998 DiplomaOBJ: 30-D1.3k TOP: oxidation numbers KEY: assigning oxidation numbers

20. ANS: A PTS: 1 REF: June 1991 DiplomaOBJ: 30-1.2k TOP: redox reactions KEY: identifying a RA

21. ANS: C PTS: 1 REF: June 1991 DiplomaOBJ: 30-1.3s TOP: reduction tables KEY: predicting a table from data

22. ANS: D PTS: 1 REF: June 1991 DiplomaOBJ: 30-1.5k TOP: reduction table KEY: identifying the SOA

23. ANS: D PTS: 1 REF: January 1990OBJ: 30-B1.7k TOP: oxidation numbers KEY: assigning ONs

24. ANS: D PTS: 1 REF: June 1990 DiplomaOBJ: 30-B1.3s TOP: reduction tables KEY: selecting an inconsistant statement

25. ANS: A PTS: 1 REF: June 2000 OBJ: 30-B1.4kTOP: redox reaction KEY: recognizing reduction

26. ANS: B PTS: 1 REF: June 2000 DiplomaOBJ: 30-B1.7k TOP: redox reactions KEY: recognizing disproportionation

27. ANS: C PTS: 1 REF: June 2001 DiplomaOBJ: 30-B1.6k TOP: redox reactions KEY: predicting spontaneity

28. ANS: B PTS: 1 REF: June 2001 DiplomaOBJ: 30-B1.2s TOP: redox reactions KEY: products of reaction

29. ANS: D PTS: 1 REF: January 2000 DiplomaOBJ: 30-B1.3s TOP: reduction tables KEY: ordering OA from empirical data

30. ANS: D PTS: 1 REF: January 2000 DiplomaOBJ: 30-B1.7k TOP: redox reactions KEY: predicting from a table

31. ANS: A PTS: 1 REF: January 2000 DiplomaOBJ: 30-B1.3k TOP: oxidation numbersKEY: assigning ON and identifying OA given a reaction

32. ANS: C PTS: 1 REF: June 2000 DiplomaOBJ: 30-B1.4k TOP: redox reactions KEY: identify reduction

33. ANS: B PTS: 1 REF: June 2000 DiplomaOBJ: 30-B1.7k TOP: redox reaction KEY: balancing in an acid

34. ANS: B PTS: 1 REF: 2003 Released ItemsOBJ: 30-B1.4k TOP: corrosion KEY: environmental corrosion of copper

35. ANS: B PTS: 1 REF: 2005 Released itemsOBJ: 30-B1.4k TOP: corrosion of copper KEY: Statue of Liberty

36. ANS: D PTS: 1 REF: 2004 Released ItemsOBJ: 30-B1.6k TOP: spontaneity KEY: identify metals based on reactions

37. ANS: A PTS: 1 REF: 2004 Released ItemsOBJ: 30-B1.2k TOP: redox reaction KEY: identify RA

38. ANS: A PTS: 1 REF: 2004 Released itemsOBJ: 30-B1.4k TOP: redox reactions KEY: identify a half-reaction

39. ANS: A PTS: 1 REF: 2004 Released ItemsOBJ: 30-B1.7k TOP: redox reaction KEY: predicting from a table

40. ANS: C PTS: 1 OBJ: 30-B1.2k TOP: redox reactionKEY: identifying reduction

41. ANS: D PTS: 1 REF: January 2002 DiplomaOBJ: 30-B1.2k TOP: redox reaction KEY: disproportionation

42. ANS: A PTS: 1 REF: January 2002 DiplomaOBJ: 30-B1.7k TOP: redox reactions KEY: identifying a reduction half reaction

43. ANS: D PTS: 1 REF: January 2002 DiplomaOBJ: 30-B1.6k TOP: spontaneity of reactions KEY: differentiate between two RA

44. ANS: C PTS: 1 REF: January 2002 DiplomaOBJ: 30-B1.8k TOP: redox titration KEY: concentration of sample

45. ANS: A PTS: 1 REF: January 2002 DiplomaOBJ: 30-B1.2s TOP: redox titration KEY: qualitative observations

46. ANS: C PTS: 1 REF: January 2002 DiplomaOBJ: 30-B1.2s TOP: redox titration KEY: selecting a titrant

47. ANS: C PTS: 1 REF: January 2002 DiplomaOBJ: 30-B1.6k TOP: redox reactions KEY: predicting from a table

48. ANS: C PTS: 1 REF: January 2002 DiplomaOBJ: 30-B1.4k TOP: redox reaction KEY: identifying RA

49. ANS: A PTS: 1 REF: June 2001 DiplomaOBJ: 30-B2.7k TOP: voltaic cell KEY: prediction of cell potential

50. ANS: C PTS: 1 REF: June 2001 DiplomaOBJ: 30-B1.7k TOP: redox equations KEY: balancing in an acid

51. ANS: B PTS: 1 REF: June 2001 DiplomaOBJ: 30-B1.7k TOP: redox reactions KEY: reduction half-reaction

52. ANS: A PTS: 1 REF: June 2001 DiplomaOBJ: 30-B1.8k TOP: redox titration KEY: calculation of [iron(II) ions]

53. ANS: A PTS: 1 REF: June 2001 DiplomaOBJ: 30-B1.7k TOP: redox reaction KEY: predicting from a table

54. ANS: B PTS: 1 REF: January 2001 DiplomaOBJ: 30-B1.3s TOP: spontaneity of reaction KEY: experimental data

55. ANS: A PTS: 1 REF: January 2001 DiplomaOBJ: 30-B1.3s TOP: reduction table KEY: selecting the SRA

56. ANS: A PTS: 1 REF: June 1999 DiplomaOBJ: 30-B1.3k TOP: oxidation numbers KEY: decrease

57. ANS: D PTS: 1 REF: June 1999 DiplomaOBJ: 30-B1.7k TOP: reactions KEY: predicting from a table

58. ANS: A PTS: 1 REF: June 1999 DiplomaOBJ: 30-B1.7k TOP: reactions KEY: predicting from a table

59. ANS: C PTS: 1 REF: June 1999 DiplomaOBJ: 30-B1.7k TOP: reaction KEY: identifying the oxidation half-reaction

60. ANS: A PTS: 1 REF: June 1999 DiplomaOBJ: 30-B1.3s TOP: predicting table KEY: experimental results

61. ANS: C PTS: 1 REF: January 1999 DiplomaOBJ: 30-B1.7k TOP: reaction KEY: predicting from a table

62. ANS: A PTS: 1 REF: January 1999 DiplomaOBJ: 30-B1.3s TOP: predicting table KEY: from experimental data

63. ANS: A PTS: 1 REF: January 1999 DiplomaOBJ: 30-B1.7k TOP: predicting a reaction KEY: from a table

64. ANS: D PTS: 1 REF: January 1999 DiplomaOBJ: 30-B1.7k TOP: activity series KEY: order of reaction

65. ANS: C PTS: 1 REF: January 1998 DiplomaOBJ: 30-B1.3s

66. ANS: A PTS: 1 REF: January 1998 DiplomaOBJ: 30-B1.4k

67. ANS: C PTS: 1 REF: January 1998 DiplomaOBJ: 30-B1.6k

68. ANS: D PTS: 1 REF: January 1998 DiplomaOBJ: 30-B1.6k

69. ANS: D PTS: 1 REF: January 1996 Diploma

OBJ: B1.3k70. ANS: C PTS: 1 REF: January 1996 Diploma

OBJ: 30-B1.3s71. ANS: B PTS: 1 REF: January 1996 Diploma

OBJ: 30-B1.6k72. ANS: D PTS: 1 REF: January 1996 Diploma

OBJ: 30-B1.6k73. ANS: A PTS: 1 REF: January 1996 Diploma

OBJ: 30-B1.3s74. ANS: B PTS: 1 REF: 2005 Released items

OBJ: 30-B1.4k TOP: oxidation KEY: identification in a reaction75. ANS: A PTS: 1 REF: 2005 Released items

OBJ: 30-B1.2s TOP: SOA KEY: from a table76. ANS: B PTS: 1 REF: 2005 Released items

OBJ: 30-B1.6k TOP: predicting spontaneity KEY: from a table77. ANS: D PTS: 1 REF: 2005 Released items

OBJ: 30-D1.7k TOP: balancing KEY: under acidic conditions78. ANS: B PTS: 1 REF: 2005 Released items

OBJ: 30-D1.7k TOP: change in oxidation number KEY: given balanced equation79. ANS: A PTS: 1 REF: June 1992 Diploma

OBJ: 30-B2.5k TOP: cell chemistry KEY: reference half-cells80. ANS: D PTS: 1 REF: June 1992 Diploma

OBJ: 30-B2.6k TOP: cell chemistry KEY: E°net81. ANS: C PTS: 1 REF: June 1992 Diploma

OBJ: 30-B2.1k TOP: electrochemical cells KEY: electron flow82. ANS: A PTS: 1 REF: June 1992 Diploma

OBJ: 30-B2.8k TOP: electrolytic cells KEY: Faraday's calculation83. ANS: B PTS: 1 REF: June 1992 Diploma

OBJ: 30-B2.6k TOP: voltaic cells KEY: predicting voltage84. ANS: B PTS: 1 REF: June 1997 Diploma

OBJ: 30-B2.2sts TOP: cells KEY: corrosion85. ANS: A PTS: 1 REF: June 1997 Diploma

OBJ: 30-B2.2sts TOP: cells KEY: corrosion of pipes86. ANS: D PTS: 1 REF: June 1997 Diploma

OBJ: 30-B2.3k TOP: electrolytic cells KEY: electroplating87. ANS: D PTS: 1 REF: June 1997 Diploma

OBJ: 30-B2.7k TOP: cells KEY: spontaneity of reaction88. ANS: A PTS: 1 REF: June 1997 Diploma

OBJ: 30-B2.2k TOP: voltaic cells KEY: description89. ANS: D PTS: 1 REF: June1997 Diploma

OBJ: 30-B2.2k TOP: cells KEY: differences between voltaic and electrolytic90. ANS: C PTS: 1 REF: June 1997 Diploma

OBJ: 30-B2.3k TOP: voltaic cells KEY: predictions91. ANS: A PTS: 1 REF: June 1997 Diploma

OBJ: 30-B2.3s TOP: voltaic cells KEY: predictions92. ANS: D PTS: 1 REF: June 1998 Diploma

OBJ: 30-B2.1sts TOP: electrolysis KEY: commercial use93. ANS: C PTS: 1 REF: June 1998 Diploma

OBJ: 30-B2.1sts TOP: electrolysis of sodium chloride KEY: design of cells

94. ANS: B PTS: 1 REF: June 1998 DiplomaOBJ: 30-B2.1 sts TOP: electrolysis of NaCl KEY: cell design

95. ANS: D PTS: 1 REF: June 1998 DiplomaOBJ: 30-B2.3k TOP: electrolysis of sodium chloride KEY: products of reaction

96. ANS: C PTS: 1 REF: June 1998 DiplomaOBJ: 30-B2.8k TOP: electrolysis of sodium chloride KEY: calculation of time

97. ANS: B PTS: 1 REF: June 1998 DiplomaOBJ: 30-B2.8k TOP: electrolysis of sodium chloride KEY: calculation of mass

98. ANS: B PTS: 1 REF: January 2000 DiplomaOBJ: 30-B2.6k TOP: corrosion of iron KEY: calculation of potential

99. ANS: A PTS: 1 REF: January 2000 DiplomaOBJ: 30-B2.3k TOP: corrosion KEY: sacrifical anode

100. ANS: C PTS: 1 REF: January 2000 DiplomaOBJ: 30-B2.2sts TOP: corrosion KEY: salt on highways

101. ANS: A PTS: 1 REF: June 2000 DiplomaOBJ: 30-B1.7k TOP: net equation KEY: prediction from the table

102. ANS: A PTS: 1 REF: June 2000 DiplomaOBJ: 30-B2.8k TOP: Faraday calculationKEY: calculate mass given time and current

103. ANS: D PTS: 1 REF: June 2000 DiplomaOBJ: 30-B1.3k TOP: redox reactions KEY: identifying electron transfer

104. ANS: C PTS: 1 REF: June 2000 DiplomaOBJ: 30-B2.8k TOP: cell stoich KEY: calculation of mass from mass consumed

105. ANS: A PTS: 1 REF: June 2000 DiplomaOBJ: 30-B2.3k TOP: standard cell notation KEY: predicting net ionic equation

106. ANS: A PTS: 1 REF: June 2000 DiplomaOBJ: 30-B2.3k TOP: voltaic cell KEY: identify the oxidation half-reaction

107. ANS: A PTS: 1 REF: June 2000 DiplomaOBJ: 30-B2.3k TOP: voltaic cell KEY: identify the SOA

108. ANS: B PTS: 1 REF: June 2000 DiplomaOBJ: 30-B2.1k TOP: voltaic cell KEY: electron flow and pH change

109. ANS: B PTS: 1 REF: June 2000 DiplomaOBJ: 30-B2.6k TOP: voltaic cell KEY: identify the anode from voltage

110. ANS: C PTS: 1 REF: 2007 Released ItemsOBJ: 30-B2,6k TOP: battery chemistryKEY: calculation of reduction potential for a half-reaction

111. ANS: A PTS: 1 REF: 2007 Released ItemsOBJ: 30-B2.7k TOP: voltaic cells KEY: identify the SRA

112. ANS: D PTS: 1 REF: 2007 Released ItemsOBJ: 30-B2.1s TOP: voltaic cell KEY: cation migration

113. ANS: D PTS: 1 REF: 2007 Released ItemsOBJ: 30-B2.2sts TOP: corrosion KEY: sacrifical anode

114. ANS: B PTS: 1 REF: January 2002 DiplomaOBJ: 30-B2.2k TOP: electrolysis KEY: energy change

115. ANS: A PTS: 1 REF: January 2002 DiplomaOBJ: 30-B2.8k TOP: Electrolysis KEY: Faraday calculation

116. ANS: D PTS: 1 REF: January 2002 DiplomaOBJ: 30-B2.2sts TOP: corrosion KEY: prevention


OBJ: 30-B2.1s TOP: voltaic cell KEY: anode selection118. ANS: C PTS: 1 REF: January 2002 Diploma

OBJ: 30-B2.6k TOP: voltaic cells KEY: predicting E° cathode119. ANS: C PTS: 1 REF: January 2002 Diploma

OBJ: 30-B2.8k TOP: cell stoich KEY: mol of e- transferred120. ANS: D PTS: 1 REF: January 2002 Diploma

OBJ: 30-B2.6k TOP: voltaic cell KEY: predicting net cell equation and potential121. ANS: A PTS: 1 REF: June 2001 Diploma

OBJ: 30-B2.3sts TOP: fuel cell KEY: ecological perspective122. ANS: D PTS: 1 REF: June 2001 Diploma

OBJ: 30-B2.3k TOP: electrolytic cell KEY: predicting cathode reaction123. ANS: A PTS: 1 REF: June 2001 Diploma

OBJ: 30-B2.3k TOP: battery KEY: predicting RA124. ANS: A PTS: 1 REF: June 2001 Diploma

OBJ: 30-B2.1k TOP: battery KEY: definition of salt bridge125. ANS: A PTS: 1 REF: January 1996 Diploma

OBJ: 30-B2.3k126. ANS: C PTS: 1 REF: January 1996 Diploma

OBJ: 30-B2.3s127. ANS: B PTS: 1 REF: June 2001 Diploma

OBJ: 30-B2.1s TOP: voltaic cell KEY: identifying an error in construction128. ANS: C PTS: 1 REF: June 2001 Diploma

OBJ: 30-B2.3k TOP: electrolysis KEY: identification of cathode reaction129. ANS: C PTS: 1 REF: January 2001 Diploma

OBJ: 30-B2.3k TOP: battery KEY: identification of the OA130. ANS: D PTS: 1 REF: January 2001 Battery

OBJ: 30-B2.3k TOP: voltaic cell KEY: reduction half-reaction131. ANS: B PTS: 1 REF: January 2001 Diploma

OBJ: 30-B2.6k TOP: voltaic cell KEY: calculation of potential132. ANS: C PTS: 1 REF: January 2001 Diploma

OBJ: 30-B2.3k TOP: voltaic cell KEY: predict net equation and potential133. ANS: A PTS: 1 REF: January 2001 Diploma

OBJ: 30-B2.1k TOP: voltaic cell KEY: cell details134. ANS: D PTS: 1 REF: January 2001 Diploma

OBJ: 30-B2.2k TOP: voltaic cell KEY: details135. ANS: C PTS: 1 REF: June 1999 Diploma

OBJ: 30-B2.6k TOP: identifying an oxidation half-reactionKEY: given cell potential and reduction half

136. ANS: A PTS: 1 REF: June 1999 DiplomaOBJ: 30-B2.2sts TOP: corrosion protection KEY: sacrificial anode

137. ANS: C PTS: 1 REF: June 1999 DiplomaOBJ: 30-B2.7k TOP: electrolysis KEY: predicting products

138. ANS: B PTS: 1 REF: June 1999 DiplomaOBJ: 30-B2.5s TOP: reference half cell KEY: change to copper half-reaction

139. ANS: A PTS: 1 REF: June 1999 DiplomaOBJ: 30-B2.6k TOP: voltaic cell KEY: predicting cell potential

140. ANS: B PTS: 1 REF: June 1999 DiplomaOBJ: 30-B2.3s TOP: electrolysis KEY: identifying products


OBJ: 30-B2.3s TOP: electroplating KEY: site of reduction142. ANS: C PTS: 1 REF: January 1999 Diploma

OBJ: 30-B2.3s TOP: electrolysis KEY: products of cell143. ANS: A PTS: 1 REF: January 1999 Diploma

OBJ: 30-B2.7k TOP: spontaneous reaction KEY: given OA144. ANS: A PTS: 1 REF: January 1999 Diploma

OBJ: 30-B2.8k TOP: Faraday calculationKEY: mass change at anode given current and time

145. ANS: B PTS: 1 REF: January 1999 DiplomaOBJ: 30-B2.3k TOP: reduction potential KEY: selecting from the table

146. ANS: A PTS: 1 REF: January 1999 DiplomaOBJ: 30-B2.1s TOP: voltaic cells KEY: identifying variables

147. ANS: B PTS: 1 REF: January 1998 DiplomaOBJ: 30-B2.3s

148. ANS: B PTS: 1 REF: January 1998 DiplomaOBJ: 30-B2.2k


150. ANS: C PTS: 1 REF: January 1998OBJ: 30-B2.3k


152. ANS: B PTS: 1 REF: January 1998 DiplomaOBJ: 30-B2.3s





157. ANS: C PTS: 1 REF: January 1996 DiplomaOBJ: 30-B2.3s

158. ANS: D PTS: 1 REF: 2005 Released itemsOBJ: 30-B1.2sts TOP: corrosion KEY: econmic and ecological

159. ANS: D PTS: 1 REF: 2005 Released itemsOBJ: 30-B2.3s TOP: voltaic cells KEY: characteristics

160. ANS: B PTS: 1 REF: 2005 Released itemsOBJ: 30-B2.6k TOP: identity of anode KEY: given cathode and potential

161. ANS: D PTS: 1 REF: 2005 Released itemsOBJ: 30-B2.3s TOP: electrolysis KEY: identifying products

162. ANS: A PTS: 1 REF: 2005 Released itemsOBJ: 30-B2.3k TOP: electrolytic cell KEY: reaction at the anode

163. ANS: C PTS: 1 REF: 2005 Released itemsOBJ: 30-B2.8k TOP: calculating time KEY: given current and mass

NUMERIC RESPONSE

164. ANS: 4646

PTS: 1 REF: June 1997 Diploma OBJ: 30-B1.3kTOP: electrochemistry KEY: oxidation numbers

165. ANS: 2143

PTS: 1 REF: June 1997 OBJ: 30-B1.5k TOP: electrochemistryKEY: strength of OA

166. ANS: 4746

PTS: 1 REF: June 1998 Diploma OBJ: 30-B1.7kTOP: redox equations KEY: balancing equations

167. ANS: 8.58

PTS: 1 REF: June 1998 Diploma OBJ: 30-B1.2sTOP: redox titration KEY: calculating an average volume

168. ANS: 6.65

PTS: 1 REF: June 1998 Diploma OBJ: 30-B1.8kTOP: redox titration KEY: calculating a concentration

169. ANS: 2121

PTS: 1 REF: June 2000 Diploma OBJ: 30-B1.7kTOP: redox equations KEY: balancing equations

170. ANS: 2431

PTS: 1 REF: June 2000 Diploma OBJ: 30-B1.6kTOP: redox reaction KEY: order of reaction

171. ANS: 1356

PTS: 1 REF: January 2000 Diploma OBJ: 30-B1.3kTOP: redox reactions KEY: identifying redox reactions

172. ANS: xxx

PTS: 1 REF: January 2000 Diploma OBJ: 30-B1.2sTOP: redox titration KEY: calculation of an average volume

173. ANS: xxx

PTS: 1 REF: January 2000 Diploma OBJ: 30-B1.8kTOP: redox titration KEY: calculation of concentration

174. ANS: 1.79

PTS: 1 REF: 2004 Released Items OBJ: 30-B1.8kTOP: redox reaction KEY: solution stoich

175. ANS: 2112

PTS: 1 REF: January 2002 Diploma OBJ: 30-B1.7kTOP: redox reactions KEY: balancing in an acid

176. ANS: 3.29

PTS: 1 REF: January 2002 Diploma OBJ: 30-B1.8kTOP: redox reactions KEY: titration calculations

177. ANS: 37.0

PTS: 1 REF: June 2001 Diploma OBJ: 30-B1.8kTOP: redox reactions KEY: mass calculation

178. ANS: 2314

PTS: 1 REF: January 2001 Diploma OBJ: 30-B1.7kTOP: predicting reactions KEY: from the table

179. ANS: 5234

PTS: 1 REF: June 1999 Diploma OBJ: 30-B1.4kTOP: reactions KEY: identifying redox reactions

180. ANS: 2323

PTS: 1 REF: June 1999 Diploma OBJ: 30-B1.7kTOP: equations KEY: balancing using ON

181. ANS: 2415

PTS: 1 REF: June 1999 Diploma OBJ: 30-B1.7kTOP: oxidation numbers KEY: assigning in compounds

182. ANS: 3.04

PTS: 1 REF: January 1999 Diploma OBJ: 30-B1.8kTOP: stoichiometry KEY: mass of metal reacted

183. ANS:16.5

PTS: 1 REF: January 1998 Diploma OBJ: 30-B1.8k184. ANS: 2042

PTS: 1 REF: January 1998 Diploma OBJ: 30-B1.3k185. ANS: 6.00


PTS: 1 REF: 2005 Released items OBJ: 30-B1.7kTOP: oxidation numbers KEY: assigning in substances

187. ANS: 5876

PTS: 1 REF: 2005 Released items OBJ: 30-B1.3sTOP: ranking OA KEY: from reaction data

188. ANS: 3.24

PTS: 1 REF: June 1992 Diploma OBJ: 30-B2.8kTOP: voltaic cells KEY: Faraday calculation

189. ANS: 0.00

PTS: 1 REF: June 1992 Diploma OBJ: 30-B2.6k, 30-B2.1sTOP: voltaic cells KEY: predicting potentials

190. ANS: 2.32

PTS: 1 REF: June 1997 Diploma OBJ: 30-B2.8kTOP: cells KEY: corrosion

191. ANS: 32.3

PTS: 1 REF: June 1997 Diploma OBJ: 30-B2.8kTOP: cells KEY: calculation of mass

192. ANS: 2461

PTS: 1 REF: June 1998 Diploma OBJ: 30-B2.1kTOP: voltaic cells KEY: labelling diagram

193. ANS: 1845 or 4518

PTS: 1 REF: June 1998 Diploma OBJ: 30-B2.6kTOP: voltaic cells KEY: predict materials given voltage

194. ANS: 1.50

PTS: 1 REF: January 2000 Diploma OBJ: 30-B2.6kTOP: voltaic cell KEY: calculation of potential

195. ANS: 8.05

PTS: 1 REF: June 2000 Diploma OBJ: 30-B2.8kTOP: Faraday calculation KEY: calculate mass when given n electrons

196. ANS: 1.10

PTS: 1 REF: June 2000 Diploma OBJ: 30-B2.6kTOP: cell potential KEY: calculation E°net

197. ANS: 6143

PTS: 1 REF: 2003 Released Items OBJ: 30-B2.1kTOP: voltaic cell KEY: labelling a cell

198. ANS:1534

PTS: 1 REF: 2006 Released items OBJ: 30-B2.1kTOP: electrolysis KEY: label diagram

199. ANS: 10.7

PTS: 1 REF: 2007 Released Items OBJ: 30-B2.8kTOP: voltaic cell KEY: calculation of mass consumed given time and current

200. ANS: 2145

PTS: 1 REF: January 2002 Diploma OBJ: 30-B2.1kTOP: voltaic cells KEY: identifying parts of a cell

201. ANS: 4.59

PTS: 1 REF: January 2002 Diploma OBJ: 30-B2.8kTOP: cell stoich KEY: mol of metal electroplated

202. ANS: 2654

PTS: 1 REF: June 2001 Diploma OBJ: 30-B2.1kTOP: fuel cell KEY: labelling a diagram

203. ANS: 86.8

PTS: 1 REF: June 2001 Diploma OBJ: 30-B2.8kTOP: electrolysis calculation KEY: calculating time to deposit a specific mass

204. ANS:1.59

PTS: 1 REF: June 2001 Diploma OBJ: 30-B2.6kTOP: battery KEY: calculate potential given half-reaction potentials

205. ANS: 3.18

PTS: 1 REF: January 1996 Diploma OBJ: 30-B2.6k206. ANS:

6.18

PTS: 1 REF: January 2001 Diploma OBJ: 30-B2.6kTOP: voltaic cell KEY: voltage in series

207. ANS: 0.44

PTS: 1 REF: January 2001 Diploma OBJ: 30-B2.6kTOP: voltaic cell KEY: calculate a E° from a net potential

208. ANS: 56.2

PTS: 1 REF: January 2001 Diploma OBJ: 30-B2.8kTOP: voltaic cell KEY: mass change of anode

209. ANS: 4386

PTS: 1 REF: June 1999 Diploma OBJ: 30-B2.1kTOP: electrolytic cell KEY: identifying components

210. ANS: 3.46

PTS: 1 REF: June 1999 Diploma OBJ: 30-B2.8kTOP: Faraday law KEY: min calculation

211. ANS: 1.89


PTS: 1 REF: January 1999 Diploma OBJ: 30-B2.3s213. ANS: 3.36

PTS: 1 REF: January 1998 Diploma OBJ: 30-B2.8k

214. ANS: 2.23

PTS: 1 REF: January 1996 Diploma OBJ: 30-B2.8k215. ANS:

0.56

PTS: 1 REF: 2005 Released items OBJ: 30-B2.6kTOP: electrochemical cell KEY: net potential

216. ANS: 6143

PTS: 1 REF: 2005 Released items OBJ: 30-B2.1sTOP: voltaic cell KEY: identify components

SHORT ANSWER

217. ANS:1a. 1 mark - balanced equation

1 mark - identify the OA and RA1 mark - identify the #e lost and gained

1b. 1 mark - correct method1 mark - correct substitution1 mark - correct answer

1c. 1 mark - choice of RA1 mark - justification of choice

PTS: 1 REF: 2003 Released Items OBJ: 30-B1.7k, 30-B1.8kTOP: redox KEY: predicting, balancing, calculation of amounts

218. ANS:Unknown A isUnknown B isUnknown C isUnknown D is

PTS: 1 REF: June 1992 Diploma OBJ: 30B1.5kTOP: spontaneity KEY: identification of compounds from a table

219. ANS:Key (2 marks) - a working electrolytic cellSupport marks - 1 mark - labelled anode, cathode, electrolyte, power source 1 mark - an aqueous gold(III) solution, and identity of an inert anode and the iron ring as the cathode 1 mark - a net cell equation showing the reduction of gold(III) and the oxidation of water (or the SOA) and the correct potential for the cell described

PTS: 1 OBJ: 30-B TOP: electrolysis KEY: describing an electrolytic cell220. ANS:

xxx

PTS: 1221. ANS:

1a. Zinc (1 mark)0 to +2 (1 mark)

1b. correct method (1 mark)correct substitution (1 mark)correct answer - 27.3 h (or an answer consistent with their choice in a) (1 mark)

1c. Choice (1 mark)Perspectives (1 mark each)

PTS: 1 REF: January 2000 Diploma OBJ: 30-B2.3sTOP: batteries KEY: ID anode, Faraday's calculation, STS issue

222. ANS:Key - a working voltaic cell (has electrolytes, salt bridge, electrodes, connecting wire) 2 marksSupport half-reactions and potential calculation - 1 mark

labelled diagram (identify of electrodes and electrolytes, salt bridge) - 1 mark

evidence at the cathode and evidence at the anode - 1 mark

PTS: 1 REF: June 2004 Diploma OBJ: 30-B2.1kTOP: voltaic cell KEY: diagram, half-reactions, potential, evidence

223. ANS:Key a design that maniplulates a factor and measures time of operation - 2 marksSupportdetails in procedure (steps, amounts, concentrations) 1 mark

identification of variables - 1 markbalanced net ionic and potential - 1 mark

PTS: 1 REF: June 2005 Diploma OBJ: 30-B2.1sTOP: voltaic cell KEY: experiment, equations and potential, variables

224. ANS:1a. 1 mark - labeled anode reaction (oxidation of zinc)

1 mark - labeled cathode reaction (reduction of oxygen)1b. 1 mark - net ionic equation

1 mark - potential1c. 1 mark - correct method

1 mark - correct value1d. 1 mark - disadvantage

1 mark - explanation

PTS: 1 REF: June 2006 Diploma OBJ: 30-B2.3sTOP: zinc-air battery KEY: reactions, electrodes, E°net, Faradays

225. ANS:1a. 1 mark - electrodes

1 mark - electrolytes/salt bridge1 mark - movement of cations and anions1 mark - movement of electrons

1b. 1 mark - balanced equation1 mark - potential

1c. 1 mark - evidence at anode1 mark - evidence at cathode

PTS: 1 REF: January 2007 OBJ: 30-B2.3s

TOP: voltaic cell KEY: diagram and labels, half-reactions, E°net, evidence226. ANS:

Key 2 marks - an experiment in which copper(II) ions is manipulated and voltage measured.

Support 1 mark - details (ie. steps, concentrations, amounts)1 mark - diagram with electrodes, electrolytes, salt bridge and voltmeter1 mark - identification of variables

PTS: 1 REF: June 2007 Diploma OBJ: 30-B2.1sTOP: voltaic cell KEY: design, diagram, variables

227. ANS:xx

PTS: 1228. ANS:

Key 2 marks -prevention of oxidation of iron pipe by oxygen and water Support1 mark - corrosion reaction

1 mark - Mg is sacrifical anode1 mark - purpose of plastic to prevent oxygen and water contact

PTS: 1 REF: January 1998 Diploma OBJ: 30-B2.2sts

Unit 1 - Electrochemistry Diploma Questions

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