Ch03

Stoichiometry of Formulas and EquationsChapter 3

Multiple Choice Questions

1. Calcium fluoride, CaF2, is a source of fluorine and is used to fluoridate drinking water. Calculate its E molar mass.

a. 118.15 g/molb. 99.15 g/molc. 78.07 g/mold. 59.08 g/mole. 50.01 g/mol

2. Calculate the molar mass of tetraphosphorus decaoxide, P4O10, a corrosive substance which can be E used as a drying agent.


3. Calculate the molar mass of rubidium carbonate, Rb2CO3.E


4. Calculate the molar mass of (NH4)3AsO4.E


5. Aluminum sulfate, Al2(SO4)3, is used in tanning leather, purifying water, and manufacture of E antiperspirants. Calculate its molar mass.


6. Calculate the molar mass of Ca(BO2)2·6H2O.M


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7. Magnesium fluoride is used in the ceramics and glass industry. What is the mass ofE 1.72 mol of magnesium fluoride?

a. 43.3 gb. 62.3 gc. 74.5 gd. 92.9 ge. 107 g

8. Sodium bromate is used in a mixture which dissolves gold from its ores. Calculate the mass in H grams of 4.68 mol of sodium bromate.

a. 706 gb. 482 gc. 383 gd. 32.2 ge. 0.0310 g

9. What is the mass in grams of 0.250 mol of the common antacid calcium carbonate?M

a. 4.00 102 gb. 25.0 gc. 17.0 gd. 4.00 10–2 ge. 2.50 10–3 g

10. Calculate the number of moles in 17.8 g of the antacid magnesium hydroxide, Mg(OH)2.E

a. 3.28 molb. 2.32 molc. 0.431 mold. 0.305 mole. 0.200 mol

11. Phosphorus pentachloride, PCl5, a white solid that has a pungent, unpleasant odor, is used as a E catalyst for certain organic reactions. Calculate the number of moles in 38.7 g of PCl5.


12. Aluminum oxide, Al2O3, is used as a filler for paints and varnishes as well as in the manufacture of E electrical insulators. Calculate the number of moles in 47.51 g of Al2O3.


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13. Calculate the number of oxygen atoms in 29.34 g of sodium sulfate, Na2SO4.H

a. 1.244 1023 O atomsb. 4.976 1023 O atomsc. 2.409 1024 O atomsd. 2.915 1024 O atomse. 1.166 1025 O atoms

14. Potassium dichromate, K2Cr2O7, is used in tanning leather, decorating porcelain and water proofing H fabrics. Calculate the number of chromium atoms in 78.82 g of K2Cr2O7.

a. 9.490 1025 Cr atoms b. 2.248 1024 Cr atomsc. 1.124 1024 Cr atomsd. 3.227 1023 Cr atomse. 1.613 1023 Cr atoms

15. Sulfur trioxide can react with atmospheric water vapor to form sulfuric acid that falls as acid rain. M Calculate the mass in grams of 3.65 1020 molecules of SO3.

a. 6.06 10–4 gb. 2.91 10–2 gc. 4.85 10–2 gd. 20.6 ge. 1650 g

16. Calculate the mass in grams of 8.35 1022 molecules of CBr4.M

a. 0.0217 gb. 0.139 gc. 7.21 gd. 12.7 ge. 46.0 g

17. The number of hydrogen atoms in 0.050 mol of C3H8O3 isE

a. 3.0 1022 H atomsb. 1.2 1023 H atomsc. 2.4 1023 H atomsd. 4.8 1023 H atomse. none of the above

18. Copper(II) sulfate pentahydrate, CuSO4·5H2O, is used as a fungicide and algicide. Calculate the M mass of oxygen in 1.000 mol of CuSO4·5H2O.

a. 249.7 gb. 144.0 gc. 96.00 gd. 80.00 ge. 64.00 g

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19. Lead (II) nitrate is a poisonous substance which has been used in the manufacture of special M explosives and as a sensitizer in photography. Calculate the mass of lead in 139 g of Pb(NO3)2.

a. 107 gb. 90.8 gc. 87.0 gd. 83.4 ge. 62.6 g

20. Household sugar, sucrose, has the molecular formula C12H22O11. What is the % of carbon in sucrose,M by mass?

a. 26.7 %b. 33.3 %c. 41.4 %d. 42.1 %e. 52.8 %

21. Gadolinium oxide, a colorless powder which absorbs carbon dioxide from the air, contains 86.76 mass % Gd.M Determine its empirical formula.

a. Gd2O3

b. Gd3O2

c. Gd3O4

d. Gd4O3

e. GdO

22. Hydroxylamine nitrate contains 29.17 mass % N, 4.20 mass % H, and 66.63 mass % O. Determine M its empirical formula.

a. HNOb. H2NO2

c. HN6O16

d. HN16O7

e. H2NO3

23. Hydroxylamine nitrate contains 29.17 mass % N, 4.20 mass % H, and 66.63 mass O. If its molar H mass is between 94 and 98 g/mol, what is its molecular formula?

a. NH2O5

b. N2H4O4

c. N3H3O3

d. N4H8O2

e. N2H2O4

24. A compound of bromine and fluorine is used to make UF6, which is an important chemical in processing and M reprocessing of nuclear fuel. The compound contains 58.37 mass percent bromine. Determine its

empirical formula.

a. BrFb. BrF2

c. Br2F3

d. Br3Fe. BrF3

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25. A compound containing chromium and silicon contains 73.52 mass percent chromium. Determine M its empirical formula.

a. CrSi3

b. Cr2Si3

c. Cr3Sid. Cr3Si2

e. Cr2S

26. Alkanes are compounds of carbon and hydrogen with the general formula CnH2n+2. An alkane component of M gasoline has a molar mass of between 125 and 130 g/mol. What is the value of n for this alkane?

a. 4b. 9c. 10d. 13e. 14

27. Terephthalic acid, used in the production of polyester fibers and films, is composed of carbon, H hydrogen, and oxygen. When 0.6943 g of terephthalic acid was subjected to combustion analysis it produced

1.471 g CO2 and 0.226 g H2O. What is its empirical formula?

a. C2H3O4

b. C3H4O2

c. C4H3O2

d. C5H12O4

e. C2H2O

28. Terephthalic acid, used in the production of polyester fibers and films, is composed of carbon, H hydrogen, and oxygen. When 0.6943 g of terephthalic acid was subjected to combustion analysis it produced

1.471 g CO2 and 0.226 g H2O. If its molar mass is between 158 and 167 g/mol, what is its molecular formula?

a. C4H6O7

b. C6H8O5

c. C7H12O4

d. C4H3O2

e. C8H6O4

29. Hydroxylamine hydrochloride is a powerful reducing agent which is used as a polymerization catalyst. M It contains 5.80 mass % H, 20.16 mass % N, 23.02 mass % O, and 51.02 mass % Cl. What is its

empirical formula?

a. H2N7O8Cl18

b. H2N2O2Clc. HN3O4Cl9

d. H4NOCle. H4NOCl2

30. In the combustion analysis of 0.1127 g of glucose (C6H12O6), what mass, in grams, of CO2 would M be produced?

a. 0.0451 gb. 0.0825 gc. 0.1652 gd. 0.4132 ge. 1.466 g

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31. Balance the following equation:E

B2O3(s) + HF(l) BF3(g) + H2O(l)

a. B2O3(s) + 6HF(l) 2BF3(g) + 3H2O(l)b. B2O3(s) + H6F6(l) B2F6(g) + H6O3(l)c. B2O3(s) + 2HF(l) 2BF3(g) + H2O(l)d. B2O3(s) + 3HF(l) 2BF3(g) + 3H2O(l)e. B2O3(s) + 6HF(l) 2BF3(g) + 6H2O(l)

32. Balance the following equation:E

UO2(s) + HF(l) UF4(s) + H2O(l)

a. UO2(s) + 2HF(l) UF4(s) + H2O(l)b. UO2(s) + 4HF(l) UF4(s) + 2H2O(l)c. UO2 (s) + H4F4(l) UF4 (s) + H4O2(l)d. UO2(s) + 4HF(l) UF4(s) + 4H2O(l)e. UO2(s) + 8HF(l) 2UF4(s) + 4H2O(l)

33. Balance the following equation for the combustion of benzene:E

C6H6(l) + O2(g) H2O(g) + CO2(g)

a. C6H6(l) + 9O2(g) 3H2O(g) + 6CO2(g)b. C6H6(l) + 9O2(g) 6H2O(g) + 6CO2(g)c. 2C6H6(l) + 15O2(g) 6H2O(g) + 12CO2(g)d. C6H6(l) + 15O2(g) 3H2O(g) + 6CO2(g)e. 2C6H6(l) + 9O2(g) 6H2O(g) + 12CO2(g)

34. Balance the following equation:M

C8H18O3(l) + O2(g) H2O(g) + CO2(g)

a. C8H18O3(l) + 8O2(g) 9H2O(g) + 8CO2(g)b. C8H18O3(l) + 11O2(g) 9H2O(g) + 8CO2(g)c. 2C8H18O3(l) + 22O2(g) 9H2O(g) + 16CO2(g)d. C8H18O3(l) + 13O2(g) 18H2O(g) + 8CO2(g)e. 2C8H18O3(l) + 17O2(g) 18H2O(g) + 16CO2(g)

35. Balance the following equation:M

Ca3(PO4)2(s) + SiO2(s) + C(s) CaSiO3(s) + CO(g) + P4(s)

a. Ca3(PO4)2(s) + 3SiO2(s) + 8C(s) 3CaSiO3(s) + 8CO(g) + P4(s)b. Ca3(PO4)2(s) + 3SiO2(s) + 14C(s) 3CaSiO3(s) + 14CO(g) + P4(s)c. Ca3(PO4)2(s) + 3SiO2(s) + 8C(s) 3CaSiO3(s) + 8CO(g) + 2P4(s)d. 2Ca3(PO4)2(s) + 6SiO2(s) + 10C(s) 6CaSiO3(s) + 10CO(g) + P4(s)e. 2Ca3(PO4)2(s) + 6SiO2(s) + 10C(s) 6CaSiO3(s) + 10CO(g) + 4P4(s)

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36. Sulfur dioxide reacts with chlorine to produce thionyl chloride (used as a drying agent for inorganicE halides) and dichlorine oxide (used as a bleach for wood, pulp and textiles).

SO2(g) + 2Cl2(g) SOCl2(g) + Cl2O(g)

If 0.400 mol of Cl2 reacts with excess SO2, how many moles of Cl2O are formed?


37. Aluminum will react with bromine to form aluminum bromide (used as an acid catalyst in E organic synthesis).

Al(s) + Br2(l) Al2Br6(s) [unbalanced]

How many moles of Al are needed to form 2.43 mol of Al2Br6?


38. Ammonia will react with fluorine to produce dinitrogen tetrafluoride and hydrogen fluoride (used in E production of aluminum, in uranium processing, and in frosting of light bulbs).

2NH3(g) + 5F2(g) N2F4(g) + 6HF(g)

How many moles of NH3 are needed to react completely with 13.6 mol of F2?


39. Ammonia, an important source of fixed nitrogen that can be metabolized by plants, is produced M using the Haber process in which nitrogen and hydrogen combine.

N2(g) + 3H2(g) 2NH3(g)

How many grams of nitrogen are needed to produce 325 grams of ammonia?

a. 1070 gb. 535 gc. 267 gd. 178 ge. 108 g

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40. How many grams of sodium fluoride (used in water fluoridation and manufacture of insecticides) M are needed to form 485 g of sulfur tetrafluoride?

3SCl2(l) + 4NaF(s) SF4(g) + S2Cl2(l) + 4NaCl(s)

a. 1940 gb. 1510 gc. 754 gd. 205 ge. 51.3 g

41. How many grams of oxygen are needed to react completely with 200.0 g of ammonia, NH3?M

4NH3(g) + 5O2(g) 4NO(g) + 6H2O(g)

a. 469.7 gb. 300.6 gc. 250.0 gd. 3.406 ge. 2.180 g

42. Phosphine, an extremely poisonous and highly reactive gas, will react with oxygen to form M tetraphosphorus decaoxide and water.

PH3(g) + O2(g) P4O10(s) + H2O(g) [unbalanced]

Calculate the mass of P4O10(s) formed when 225 g of PH3 reacts with excess oxygen.

a. 1880 gb. 940. gc. 900. gd. 470 ge. 56.3 g

43. Potassium chlorate (used in fireworks, flares and safety matches) forms oxygen and potassium M chloride when heated.

KClO3(s) KCl(s) + O2(g) [unbalanced]

How many grams of oxygen are formed when 26.4 g of potassium chlorate is heated?

a. 223 gb. 99.1 gc. 10.3 gd. 6.86 ge. 4.60 g

44. Aluminum metal reacts with chlorine gas to form solid aluminum trichloride, AlCl3. What mass of M chlorine gas is needed to react completely with 163 g of aluminum?

a. 214 gb. 245 gc. 321 gd. 489 ge. 643 g

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45. Lead(II) sulfide was once used in glazing earthenware. It will also react with hydrogen peroxide to form H lead(II) sulfate and water. How many grams of hydrogen peroxide are needed to react completely with

265 g of lead(II) sulfide?

a. 151 gb. 123 gc. 50.3 gd. 37.7 ge. 9.41 g

46. An important reaction sequence in the industrial production of nitric acid is the following:M N2(g) + 3H2(g) 2NH3(g)

4NH3(g) + 5O2(g) 4NO(g) + 6H2O(l)

Starting from 20.0 mol of nitrogen gas in the first reaction, how many moles of oxygen gas are required in the second one?

a. 12.5 mol O2

b. 20.0 mol O2

c. 25.0 mol O2

d. 50.0 mol O2

e. 100. mol O2

47. In a blast furnace, elemental iron is produced from a mixture of coke (C), iron ore (Fe3O4) and otherE reactants. An important reaction sequence is

2C(s) + O2(g) 2CO(g) Fe3O4(s) + 4CO(g) 3Fe(l) + 4CO2(g)

How many moles of iron can be formed in this sequence when 1.00 mol of carbon, as coke, is consumed?

a. 6.00 mol Feb. 3.00 mol Fec. 1.33 mol Fed. 1.25 mol Fee. 0.750 mol Fe

48. Aluminum oxide (used as an adsorbent or a catalyst for organic reactions) forms when aluminum reacts H with oxygen.

4Al(s) + 3O2(g) 2Al2O3(s)

A mixture of 82.49 g of aluminum (M = 26.98 g/mol) and 117.65 g of oxygen (M = 32.00 g/mol) is allowed to react. What mass of aluminum oxide (M = 101.96 g/mol) can be formed?

a. 155.8 gb. 200.2 gc. 249.9 gd. 311.7 ge. 374.9 g

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49. Aluminum reacts with oxygen to produce aluminum oxide which can be used as an adsorbent, H desiccant or catalyst for organic reactions.

4Al(s) + 3O2(g) 2Al2O3(s)

A mixture of 82.49 g of aluminum (M = 26.98 g/mol) and 117.65 g of oxygen (M = 32.00 g/mol) is allowed to react. Identify the limiting reactant and determine the mass of the excess reactant present in the vessel when the reaction is complete.

a. Oxygen is the limiting reactant; 19.81 g of aluminum remain.b. Oxygen is the limiting reactant; 35.16 g of aluminum remain.c. Aluminum is the limiting reactant; 16.70 g of oxygen remain.d. Aluminum is the limiting reactant; 35.16 g of oxygen remain.e. Aluminum is the limiting reactant; 44.24 g of oxygen remain.

50. Magnesium reacts with iron(III) chloride to form magnesium chloride (which can be used in H fireproofing wood and in disinfectants) and iron.

3Mg(s) + 2FeCl3(s) 3MgCl2(s) + 2Fe(s)

A mixture of 41.0 g of magnesium (M = 24.31 g/mol) and 175 g of iron(III) chloride (M = 162.2 g/mol) is allowed to react. What mass of magnesium chloride = 95.21 g/mol) is formed?

a. 68.5 g MgCl2 b. 77.0 g MgCl2

c. 71.4 g MgCl2

d. 107 g MgCl2

e. 154 g MgCl2

51. Magnesium (used in the manufacture of light alloys) reacts with iron(III) chloride to form H magnesium chloride and iron.

3Mg(s) + 2FeCl3(s) 3MgCl2(s) + 2Fe(s)

A mixture of 41.0 g of magnesium (M = 24.31 g/mol) and 175 g of iron(III) chloride (M = 162.2 g/mol) is allowed to react. Identify the limiting reactant and determine the mass of the excess reactant present in the vessel when the reaction is complete.

a. Limiting reactant is Mg; 67 g of FeCl3 remain.b. Limiting reactant is Mg; 134 g of FeCl3 remain.c. Limiting reactant is Mg; 104 g of FeCl3 remain.d. Limiting reactant is FeCl3; 2 g of Mg remain.e. Limiting reactant is FeCl3; 87 g of Mg remain.

52. Potassium chloride is used as a substitute for sodium chloride for individuals with high blood pressure.H Identify the limiting reactant and determine the mass of the excess reactant remaining when 7.00 g of chlorine

gas reacts with 5.00 g of potassium to form potassium chloride.

a. Potassium is the limiting reactant; 2.47 g of chlorine remain.b. Potassium is the limiting reactant; 7.23 g of chlorine remain.c. Chlorine is the limiting reactant; 4.64 g of potassium remain.d. Chlorine is the limiting reactant; 2.70 g of potassium remain.e. No limiting reagent: the reactants are present in the correct stoichiometric ratio.

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53. Tetraphosphorus hexaoxide (M = 219.9 g/mol) is formed by the reaction of phosphorus with oxygen gas.M

P4(s) + 3O2(g) P4O6(s)

If a mixture of 75.3 g of phosphorus and 38.7 g of oxygen produce 43.3 g of P4O6, what is the percent yield for the reaction?

a. 57.5%b. 48.8%c. 38.0%d. 32.4%e. 16.3%

54. What is the percent yield for the reactionM

PCl3(g) + Cl2(g) PCl5(g)

if 119.3 g of PCl5 (M = 208.2 g/mol) are formed when 61.3 g of Cl2 (M = 70.91 g/mol) react with excess PCl3?

a. 195%b. 85.0%c. 66.3%d. 51.4%e. 43.7%

55. Methanol (CH4O) is converted to bromomethane (CH3Br) as follows:M

CH4O + HBr CH3Br + H2O

If 12.23 g of bromomethane are produced when 5.00 g of methanol is reacted with excess HBr, what is the percentage yield?

a. 40.9%b. 82.6%c. 100.%d. 121%e. 245%

56. A 0.150 M sodium chloride solution is referred to as a physiological saline solution because it has the same M concentration of salts as normal human blood. Calculate the mass of solute needed to prepare 275.0 mL of a

physiological saline solution.

a. 41.3 gb. 31.9 gc. 16.1 gd. 8.77 ge. 2.41 g

57. Sodium chlorate is used as an oxidizer in the manufacture of dyes, explosives and matches. Calculate the M mass of solute needed to prepare 1.575 L of 0.00250 M NaClO3 (M = 106.45 g/mol).

a. 419 gb. 169 gc. 0.419 gd. 0.169 ge. 0.00394 g

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58. Lithium hydroxide is used in alkaline batteries. Calculate the molarity of a solution prepared by dissolving E 1.495 moles of LiOH in enough water to give a final volume of 750. mL.

a. 1.99 Mb. 1.50 Mc. 1.12 Md. 0.502 Me. 0.00199 M

59. Hydrochloric acid is widely used as a laboratory reagent, in refining ore for the production of tin andE tantalum, and as a catalyst in organic reactions. Calculate the number of moles of HCl in 62.85 mL of

0.453 M hydrochloric acid.


60. Sodium hydroxide, also known as caustic soda, is used to neutralize acids and to treat cellulose in E making of cellophane. Calculate the number of moles of solute in 1.875 L of 1.356 M NaOH solution.


61. Calculate the molarity of a 23.55-mL solution which contains 28.24 mg of sodium sulfate (used in M dyeing and printing textiles, M = 139.04 g/mol).

a. 8.625 Mb. 1.199 Mc. 0.8339 Md. 0.2031 Me. 0.008625 M

62. When 2.61 g of solid Na2CO3 is dissolved in sufficient water to make 250. mL of solution, the E concentration of Na2CO3 is:

a. 0.0246 Mb. 10.4 Mc. 0.205 Md. 0.0985 Me. 0.141 M

63. Calcium chloride is used to melt ice and snow on roads and sidewalks and to remove water from organic M liquids. Calculate the molarity of a solution prepared by diluting 165 mL of 0.688 M calcium chloride to

925.0 mL.

a. 3.86 M b. 0.743 M c. 0.222 M d. 0.123 M e. 0.114 M

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64. What will be the final volume of a solution prepared by diluting 25 mL of 8.25 M sodium hydroxide M to a concentration of 2.40 M?

a. 330 mLb. 210 mLc. 86 mLd. 60 mLe. 7.3 mL

65. What volume, in L, of 10.0 M HCl is needed to make 2.00 L of 2.00 M HCl solution by dilution E with water?

a. 0.800 L b. 0.400 Lc. 0.200 Ld. 0.100 Le. none of the above

66. How many mL of concentrated nitric acid (HNO3, 16.0 M) should be diluted with water in order to E make 2.00 L of 2.00 M solution?

a. 32.0 mLb. 62.5 mLc. 125 mLd. 250. mLe. 500. mL

67. How many milliliters of 1.58 M HCl are needed to react completely with 23.2 g of NaHCO3

M (M = 84.02 g/mol)?

HCl(aq) + NaHCO3(s) NaCl(s) + H2O(l) + CO2(g)

a. 638 mLb. 572 mLc. 536 mLd. 276 mLe. 175 mL

68. Copper(II) sulfide, CuS, is used in the development of aniline black dye in textile printing. What is the H maximum mass of CuS which can be formed when 38.0 mL of 0.500 M CuCl2 are mixed with 42.0 mL of

0.600 M (NH4)2S? Aqueous ammonium chloride is the other product.

a. 2.41 gb. 1.82 gc. 1.21 gd. 0.909 ge. 0.044 g

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Short Answer Questions

69. Propane, C3H8, is commonly provided as a bottled gas for use as a fuel. In 0.200 mol of propaneM

a. what is the mass of propane?b. what mass of carbon is present?c. how many molecules of C3H8 are present?d. how many hydrogen atoms are present?

70. For a sample consisting of 2.50 g of methane, CH4, calculateM

a. the number of moles of methane present.b. the total number of atoms present.

71. In 0.20 mole of phosphoric acid, H3PO4

Ea. how many H atoms are there?b. what is the total number of atoms?c. how many moles of O atoms are there?

72. A compound consisting of C, H and O only, has a molar mass of 331.5 g/mol. Combustion ofH 0.1000 g of this compound caused a 0.2921 g increase in the mass of the CO2 absorber and a 0.0951 g

increase in the mass of the H2O absorber. What is the empirical formula of the compound?

73. Analysis of a white solid produced in a reaction between chlorine and phosphorus showed that it E contained 77.44% chlorine and 22.56% phosphorus. What is its empirical formula?

74. Balance the following equation for the combustion of butane, a hydrocarbon used in gas lighters:M

C4H10(g) + O2(g) CO2(g) + H2O(l)

75. Balance the equationE

B2O3(s) + NaOH(aq) Na3BO3(aq) + H2O(l)

76. Balance the following equation for partial oxidation of ammonia, an important reaction in the M production of nitric acid:

NH3(g) + O2(g) NO(g) + H2O(l)

77. Gaseous methanol (CH4O) reacts with oxygen gas to produce carbon dioxide gas and liquid water.M Write a balanced equation for this process.

78. Consider the balanced equation for the combustion of propane, C3H8

MC3H8(g) + 5O2(g) 3CO2(g) + 4H2O(l)

If propane reacts with oxygen as abovea. what is the limiting reagent in a mixture containing 5.00 g of C3H8 and 10.0 g of O2?b. what mass of CO2 is formed when 1.00 g of C3H8 reacts completely?

79. Ammonia, NH3 , is produced industrially from nitrogen and hydrogen as follows:M

N2(g) + 3H2(g) 2NH3(g)

What mass, of which starting material, will remain when 30.0 g of N2 and 10.0 g of H2 react until the limiting reagent is completely consumed?

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80. Consider the balanced equation:M

Al2S3(s) + 6H2O(l) 2Al(OH)3(s) + 3H2S(g)

If 15.0g of aluminum sulfide and 10.0g of water are allowed to react as above, and assuming a complete reaction

a. by calculation, find out which is the limiting reagent.b. calculate the maximum mass of H2S which can be formed from these reagents.c. calculate the mass of excess reagent remaining after the reaction is complete.

81. The insecticide DDT was formerly in widespread use, but now it is severely restricted owing to its H adverse environmental effects. It is prepared as follows:

C2HCl3O + 2C6H5Cl C14H9Cl5 + H2Ochloral chlorobenzene DDT

If 10.00 g of chloral were reacted with 10.00 g of chlorobenzene

a. what is the maximum amount (mol) of DDT which could be formed?b. what is the limiting reagent?c. what is the % yield, if 12.15 g of DDT is produced?

82. You are provided with a 250 mL volumetric flask, deionized water and solid NaOH. How much NaOH E should be weighed out in order to make 250. mL of 0.100 M solution?

83. A solution of methanol (CH4O) in water has a concentration of 0.200 M. What mass of methanol, E in grams, is present in 0.150 liters of this solution?

84. a. A solution of common salt, NaCl, in water has a concentration of 0.0921 M. Calculate the number of M moles of HCl contained in 50.0 mL of this solution.

b. If, instead, an NaCl solution is prepared by dissolving 10.0 g of solid NaCl in enough water to make 250. mL of solution, what is the molarity?

85. Aluminum metal dissolved in hydrochloric acid as followsM

2Al(s) + 6HCl(aq) 2AlCl3(aq) + 3H2(g)

a. What is the minimum volume of 6.0 M HCl(aq) needed to completely dissolve 3.20 g of aluminum in this reaction?

b. What mass of AlCl3 would be produced by complete reaction of 3.20 g of aluminum?

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True/False Questions

86. One mole of O2 has a mass of 16.0 g.E

87. One mole of methane (CH4) contains a total of 3 1024 atoms.E

88. The formula CH3O0.5 is an example of an empirical formula.E

89. In combustion analysis, the carbon and hydrogen contents of a substance are determined from the E CO2 and H2O, respectively, which are collected in the absorbers.

90. In combustion analysis, the oxygen content of a substance is equal to the total oxygen in the CO2 M and H2O collected in the absorbers.

91. Structural isomers have the same empirical formula but different molecular formulas.M

92. Structural isomers have the same molecular formula but different structural formulas.M

93. In a correctly balanced equation, the number of reactant molecules must equal the number of E product molecules.

94. The correct method for preparing one liter of a 1.0 M solution of X is to dissolve exactly one mole E of X in exactly one liter of water.

95. When a solution is diluted with water, the ratio of the initial to final volumes of solution is equal to E the ratio of final to initial molarities.

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Stoichiometry: Mole-Mass-Number Relationships in Chemical SystemsChapter 3

Answer Key

1. c2. b3. c4. b5. b6. b7. e8. a9. b10. d11. e12. d13. b14. d15. c16. e17. c18. b19. c20. d21. a22. b23. b

24. e25. d26. b27. c28. e29. d30. c31. a32. b33. c34. b35. d36. c37. b38. d39. c40. c41. a42. d43. c44. e45. a46. d

47. e48. a49. e50. e51. d52. a53. b54. c55. b56. e57. c58. a59. d60. a61. e62. d63. d64. c65. b66. d67. e68. b

69. a. 8.82 gb. 7.21 gc. 1.20 1023 C3H8 moleculesd. 9.64 1023 H atoms

70. a. 0.156 mol CH4

b. 4.69 1023 atoms

71. a. 3.61 1023 H atomsb. 9.64 1023 atomsc. 4.82 1023 O atoms

72. C22H35O2

73. PCl3

74. 2C4H10(g) + 13O2(g) 8CO2(g) + 10H2O(l)

75. B2O3(s) + 6NaOH(aq) 2Na3BO3(aq) + 3H2O(l)

76. 4NH3(g) + 5O2(g) 4NO(g) + 6H2O(l)

77. 2CH4O(g) + 3O2(g) 2CO2(g) + 4H2O(l)

78. a. Oxygen is the limiting reagent.b. 2.99 g CO2

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79. 3.52 g of hydrogen gas remains.

80. a. Water is the limiting reagent.b. 9.50 g of H2Sc. 1.11 g Al2S3 remains.

81. a. 0.0444 mol DDTb. Chlorobenzene is the limiting reagent.c. 77.2%

82. 1.000 g

83. 0.961 g

84. a. 0.00461 gb. 0.684 M

85. a. 59.3 mLb. 15.8 g

86. F

87. T

88. F

89. T

90. F

91. F

92. T

93. F

94. F

95. T

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Ch03

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