CHE 105 Spring 2018 Exam 2

Your Name: Your ID:

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Question #: 1

A penny contains 3.73 x 10–2 moles of zinc. How many atoms of zinc are in a penny?

A. 2.25 x 1022 atoms

B. 2.21 x 1023 atoms

C. 3.75 x 1022 atoms

D. 2.755 x 1023 atoms

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Question #: 2

For which one will 1 mole of atoms of the element have the largest mass?

A. carbon

B. lithium

C. calcium

D. sulfur

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Question #: 3

What is the molar mass of nicotine, C10H14N2? .

A. 134 g/mol

B. 148 g/mol

C. 158 g/mol

D. 162 g/mol

E. 210 g/mol

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Question #: 4

One peanut contains 80.0 milligrams of sucrose. The molecular formula of sucrose is C12H22O11 (molar mass = 342.3 g/mol). How many moles of sucrose are in a peanut? .

A. 2.34 x 10–4 moles

B. 4.33 x 10–5 moles

C. 3.33 x 10–3 moles

D. 1.33 x 10–2 moles

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Question #: 5

What percentage by mass is carbon in Al4C3? .

A. 19.7 %

B. 22.2 %

C. 25.0 %

D. 31.7 %

E. 41.2 %

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Question #: 6

How many atoms of chlorine are in 5.00 moles of Freon, CCl2F2? 1 Report your answers with three significant figures. Do NOT include units in your answer. Use the format 2.22E2 or 2.22E–2 for numbers in scientific notation.

1.

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Question #: 7

What is the empirical formula of a compound that is 62% carbon, 10.4% hydrogen, and 27.5% oxygen by mass?

A. C3HO

B. C6HO3

C. C6H12O2

D. C5H10O

E. C3H6O

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Question #: 8

What is the molecular formula for a compound that has a molar mass of 92.0 g/mol and an empirical formula of NO2? .

A. N2O3

B. N3O6

C. N2O4

D. N4O8

E. N2O5

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Question #: 9

When nail polish dissolves in ethyl acetate (nail polish remover), ethyl acetate is the 1 [solvent, solute] and nail polish is the 2 [solvent, solute].

1.

2.

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Question #: 10

One liter of pure water contains 1000. grams of H2O. What is the molarity (M) of water? .

A. 55.51 M

B. 1.89 x 104 M

C. 1.760 x 10–2 M

D. 1.000 M

E. 1000. M

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Question #: 11

How many moles of ethanol, CH3CH2OH, are contained in 548 mL of 0.0788 M ethanol solution? .

A. 4.32 × 10-2 mol

B. 2.32 × 10-2 mol

C. 6.95 × 10-2 mol

D. 1.44 × 10-2 mol

E. 5.26 × 10-2 mol

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Question #: 12

If 234 mL of water is added to a beaker that already contains 766 mL of a 1.50 M solution of NaCl , what is the final concentration of the solution? 1 M Report your answer with three significant figures. Do NOT include units in your answer.

1.

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Question #: 13

Which equation shows the balanced reaction of ethane with molecular oxygen to form carbon monoxide and water vapor?

A. 2C2H6(g) + 7O2(g) → 4CO2(g) + 4H2O(g)

B. C2H6(g) + 5O(g) → 2CO(g) + 3H2O(g)

C. 2C2H6(g) + 5O2(g) → 4CO(g) + 6H2O(g)

D. C2H6(g) + 7O(g) → 2CO2(g) + 3H2O(g)

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Question #: 14

Which compound is the precipitate in the following reaction? K2CO3(aq) + NiCl2(aq) → ? .

A. NiCO3

B. Ni3CO3

C. KCl

D. KCl2

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Question #: 15

Based on the solubility rules, which compound should be soluble in water?

A. (NH4)3PO4

B. Ca3(PO4)2

C. AlPO4

D. Ag3PO4

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Question #: 16

Which two statements are true regarding strong electrolytes?

A. Solutions of strong electrolytes conduct electricity.

B. Solutions of strong electrolytes do not conduct electricity.

C. Strong electrolytes will completely dissociate (or ionize) in water.

D. Strong electrolytes will partially dissociate (or ionize) in water.

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Question #: 17

When dissolved in water, acids produce 1 ions, while bases dissolve in water to yield 2 ions.

1.

2.

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Question #: 18

What are the two spectator ions in the reaction? Pb(NO3)2(aq) + H2SO4(aq) → PbSO4(s) + 2HNO3(aq) .

A. Pb2+(aq)

B. H+(aq)

C. NO3–(aq)

D. SO42–(aq)

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Question #: 19

What is the oxidation number of chromium in the dichromate anion, Cr2O72– ? .

A. +4

B. +6

C. +8

D. +10

E. +12

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Question #: 20

In the reaction shown below, 1 is oxidized and 2 is the reducing agent. Ni(s) + 2AgClO4(aq) → Ni(ClO4)2(aq) + 2Ag(s)

1.

2.

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Question #: 21

When the following redox reaction is balanced with the smallest possible whole number coefficients, what is the coefficient of elemental lithium? Li(s) + O2(g) → Li2O(s) .

A. 1

B. 2

C. 3

D. 4

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Question #: 22

Which two are weak acids in aqueous solutions?

A. acetic acid, C2H4O2

B. hydroiodic acid, HI

C. percholoric acid, HClO4

D. nitric acid, HNO3

E. citric acid, C6H8O7

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Question #: 23

Which two equations represent the ionization of a strong acid?

A. HCl(aq) → H+(aq) + Cl–(aq)

B. HNO3(aq) + H2O(l) →H3O+(aq) + NO3–(aq)

C. NaOH(aq) → Na+(aq) + OH–(aq)

D. HCl(aq) + NaOH(aq) →H2O(l) + NaCl(aq)

E. NaCl(aq) → Na+(aq) + Cl–(aq)

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Question #: 24

Automotive air bags inflate when sodium azide decomposes explosively into its constituent elements. 2NaN3(s) → 2Na(s) + 3N2(g) How many moles of N2 are produced by the decomposition of 2.88 mol of sodium azide? .

A. 1.92 mol

B. 8.64 mol

C. 4.32 mol

D. 0.960 mol

E. 1.44 mol

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Question #: 25

What is the limiting reactant when 40 g of magnesium reacts with 38 g of molecular oxygen? 2Mg(s) + O2(g) → 2MgO(s) .

A. magnesium

B. molecular oxygen

C. They are present in equimolar amounts, so neither is limiting.

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Question #: 26

How many moles of BCl3 are needed to produce 10.0 g of HCl? BCl3(g) + 3H2O(l) → 3HCl(aq) + B(OH)3(aq) .

A. 0.0914 mol BCl3

B. 0.274 mol BCl3

C. 0.832 mol BCl3

D. 3.17 mol BCl3

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Question #: 27

When 11.0 g of calcium metal reacts with water, 5.00 g of calcium hydroxide (molar mass = 74.10 g/mol) is produced. Given the balanced equation, what is the percent yield of the reaction? Ca(s) + 2H2O(l) → Ca(OH)2(aq) + H2(g) .

A. 12.3%

B. 24.6%

C. 45.5%

D. 61.9%

E. 84.0%

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Question #: 28

What volume of a 0.300 M KCl solution will completely react with 2.00 L of a 0.400 M Pb(NO3)2 solution based on the balanced chemical equation? 2KCl(aq) + Pb(NO3)2(aq) → PbCl2(s) + 2KNO3(aq) .

A. 5.33 L

B. 3.92 L

C. 4.51 L

D. 2.83 L

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Question #: 29

From the balanced equation for the titration reaction, how many mL of 0.00300 M phosphoric acid are required to neutralize 45.00 mL of 0.00150 M barium hydroxide solution? 3Ba(OH)2(aq) + 2H3PO4(aq) → Ba3(PO4)2(s) + 6H2O(l) .

A. 3.04 mL

B. 15.0 mL

C. 22.5 mL

D. 33.8 mL

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Question #: 30

What is the concentration in ppm (parts per million) of mercury in a 50.0 g sample of industrial wastewater containing 0.48 mg of mercury?

A. 4.8 × 10-2 ppm

B. 4800 ppm

C. 9.6 ppm

D. 96 ppm

DRAFTDo Not Use Until Posted.

CHE 105 Spring 2018 Exam 2 - Confidential

Your Name: Your ID:

attachment_for_pubExamUID_lnxp115197488942858838XX_252.jpg

Question #: 1

A penny contains 3.73 x 10–2 moles of zinc. How many atoms of zinc are in a penny?

✓A. 2.25 x 1022 atoms

B. 2.21 x 1023 atoms C. 3.75 x 1022 atoms D. 2.755 x 1023 atoms

Question #: 2

For which one will 1 mole of atoms of the element have the largest mass?

A. carbon

B. lithium ✓C. calcium

D. sulfur

Question #: 3

What is the molar mass of nicotine, C10H14N2?

.

A. 134 g/mol B. 148 g/mol C. 158 g/mol

✓D. 162 g/mol E. 210 g/mol

Question #: 4

One peanut contains 80.0 milligrams of sucrose. The molecular formula of sucrose is C12H22O

11 (molar mass = 342.3 g/mol). How many moles of sucrose are in a peanut?

.

✓A. 2.34 x 10–4 moles

B. 4.33 x 10–5 moles C. 3.33 x 10–3 moles D. 1.33 x 10–2 moles

Question #: 5

What percentage by mass is carbon in Al4C3?

.

A. 19.7 % B. 22.2 %

✓C. 25.0 % D. 31.7 % E. 41.2 %

Question #: 6

How many atoms of chlorine are in 5.00 moles of Freon, CCl2F2?     1    

Report your answers with three significant figures.  Do NOT include units in your answer.  Use

the format 2.22E2 or 2.22E–2 for numbers in scientific notation.

1. 6.02E24

Question #: 7

What is the empirical formula of a compound that is 62% carbon, 10.4% hydrogen, and 27.5%

oxygen by mass?

A. C3HO B. C6HO3 C. C6H12O2 D. C5H10O

✓E. C3H6O

Question #: 8

What is the molecular formula for a compound that has a molar mass of 92.0 g/mol and an

empirical formula of NO2?

.

A. N2O3 B. N3O6

✓C. N2O4 D. N4O8 E. N2O5

Question #: 9

When nail polish dissolves in ethyl acetate (nail polish remover), ethyl acetate is the     1    

 [solvent, solute] and nail polish is the     2     [solvent, solute].

1. solvent

2. solute

Question #: 10

One liter of pure water contains 1000. grams of H2O. What is the molarity (M) of water?

.

✓A. 55.51 M

B. 1.89 x 104 M C. 1.760 x 10–2 M D. 1.000 M E. 1000. M

Question #: 11

How many moles of ethanol, CH3CH2OH, are contained in 548 mL of 0.0788 M ethanol

solution?

.

✓A. 4.32 × 10-2 mol

B. 2.32 × 10-2 mol C. 6.95 × 10-2 mol D. 1.44 × 10-2 mol E. 5.26 × 10-2 mol

Question #: 12

If 234 mL of water is added to a beaker that already contains 766 mL of a 1.50 M solution of

NaCl , what is the final concentration of the solution? 

    1     M

Report your answer with three significant figures. Do NOT include units in your answer.

1. 1.15

Question #: 13

Which equation shows the balanced reaction of ethane with molecular oxygen to form carbon

monoxide and water vapor?

A. 2C2H6(g) + 7O2(g) → 4CO2(g) + 4H2O(g) B. C2H6(g) + 5O(g) → 2CO(g) + 3H2O(g)

✓C. 2C2H6(g) + 5O2(g) → 4CO(g) + 6H2O(g) D. C2H6(g) + 7O(g) → 2CO2(g) + 3H2O(g)

Question #: 14

Which compound is the precipitate in the following reaction?

K2CO3(aq) + NiCl2(aq)  →  ?

.

✓A. NiCO3

B. Ni3CO3 C. KCl D. KCl2

Question #: 15

Based on the solubility rules, which compound should be soluble in water?

✓A. (NH4)3PO4

B. Ca3(PO4)2 C. AlPO4 D. Ag3PO4

Question #: 16

Which two statements are true regarding strong electrolytes?

✓A. Solutions of strong electrolytes conduct electricity.

B. Solutions of strong electrolytes do not conduct electricity.

✓C. Strong electrolytes will completely dissociate (or ionize) in water. D. Strong electrolytes will partially dissociate (or ionize) in water.

Question #: 17

When dissolved in water, acids produce     1     ions, while bases dissolve in water to yield     2    

 ions.

1. hydronium|hydrogen|H+|H3O+|

2. hydroxide|OH-|

Question #: 18

What are the two spectator ions in the reaction?

Pb(NO3)2(aq) + H2SO4(aq) → PbSO4(s) + 2HNO3(aq)

.

A. Pb2+(aq)

✓B. H+(aq) ✓C. NO3

–(aq) D.  SO

42–

(aq)

Question #: 19

What is the oxidation number of chromium in the dichromate anion, Cr2O72– ?

.

A. +4

✓B. +6 C. +8 D. +10 E. +12

Question #: 20

In the reaction shown below,     1     is oxidized and     2     is the reducing agent.

Ni(s) + 2AgClO4(aq) → Ni(ClO4)2(aq) + 2Ag(s)

1. Ni|nickel|Ni(s)|

2. Ni|nickel|Ni(s)|

Question #: 21

When the following redox reaction is balanced with the smallestpossible whole number coefficients, what is the coefficient of elementallithium?

Li(s) + O2(g) → Li2O(s)

.

A. 1 B. 2 C. 3

✓D. 4

Question #: 22

Which two are weak acids in aqueous solutions?

✓A. acetic acid, C2H4O2

B. hydroiodic acid, HI C. percholoric acid, HClO4 D. nitric acid, HNO3

✓E. citric acid, C6H8O7

Question #: 23

Which two equations represent the ionization of a strong acid?

✓A. HCl(aq) → H+(aq) + Cl–(aq) ✓B. HNO3(aq) + H2O(l) →H3O+(aq) + NO3

–(aq)

C. NaOH(aq) → Na+(aq) + OH–(aq) D. HCl(aq) + NaOH(aq) →H2O(l) + NaCl(aq) E. NaCl(aq) → Na+(aq) + Cl–(aq)

Question #: 24

Automotive air bags inflate when sodium azide decomposes explosively into its constituent

elements.

2NaN3(s) → 2Na(s) + 3N2(g) 

How many moles of N2 are produced by the decomposition of 2.88 mol of sodium azide?

.

A. 1.92 mol B. 8.64 mol

✓C. 4.32 mol D. 0.960 mol E. 1.44 mol

Question #: 25

What is the limiting reactant when 40 g of magnesium reacts with 38 g of molecular oxygen?

2Mg(s) + O2(g) → 2MgO(s)

.

✓A. magnesium

B. molecular oxygen C. They are present in equimolar amounts, so neither is limiting.

Question #: 26

How many moles of BCl3 are needed to produce 10.0 g of HCl?

BCl3(g) + 3H2O(l) → 3HCl(aq) + B(OH)3(aq)

.

✓A. 0.0914 mol BCl3

B. 0.274 mol BCl3 C. 0.832 mol BCl3 D. 3.17 mol BCl3

Question #: 27

When 11.0 g of calcium metal reacts with water, 5.00 g of calcium hydroxide (molar mass = 74.10

g/mol) is produced.  Given the balanced equation, what is the percent yield of the reaction?

Ca(s) + 2H2O(l) → Ca(OH)2(aq) + H2(g)

.

A. 12.3%

✓B. 24.6% C. 45.5% D. 61.9% E. 84.0%

Question #: 28

What volume of a 0.300 M KCl solution will completely react with 2.00 L of a 0.400 M Pb(NO3)

2 solution based on the balanced chemical equation?

2KCl(aq) + Pb(NO3)2(aq)  → PbCl2

(s) + 2KNO3

(aq)

.

✓A. 5.33 L B. 3.92 L C. 4.51 L D. 2.83 L

Question #: 29

From the balanced equation for the titration reaction, how many mL of 0.00300 M phosphoric

acid are required to neutralize 45.00 mL of 0.00150 M barium hydroxide solution?

3Ba(OH)2(aq) + 2H3PO4(aq) → Ba3(PO4)2(s) + 6H2O(l)

.

A. 3.04 mL

✓B. 15.0 mL  C. 22.5 mL D. 33.8 mL

Question #: 30

What is the concentration in ppm (parts per million) of mercury in a 50.0 g sample of industrial

wastewater containing 0.48 mg of mercury?

A. 4.8 × 10-2 ppm B. 4800 ppm

✓C. 9.6 ppm D. 96 ppm