Chapter 6 1 What is the sum of the coefficients when the following

General Chemistry: Atoms First, 2e (McMurry and Fay)

Chapter 6 Chemical Arithmetic: Stoichiometry

6.1 Multiple Choice Questions

1) Which one of the following statements about balanced equations is false? In a balanced

reaction

A) atoms must be balanced on both sides of the reaction arrow.

B) mass must be conserved.

C) molecules must be balanced on both sides of the reaction arrow.

D) net charge must be balanced on both sides of the reaction arrow.

2) Which one of the following statements about balanced equations is true? A reaction is

balanced by

A) changing the charge on an ion.

B) changing the formula of the molecule.

C) multiplying by suitable coefficients.

D) rearranging atoms in a molecule.

3) What is the stoichiometric coefficient for oxygen when the following equation is balanced

using the lowest, whole-number coefficients

___ C3H8O(l) + ___ O2(g) → ___ CO2(g) + ___ H2O(l)

A) 3

B) 5

C) 7

D) 9

4) What is the sum of the coefficients when the following equation is balanced using the lowest,

whole numbered coefficients?

___ PH3(g) + ___ O2(g) → ___ P4O10(s) + ___ H2O(g)

A) 10

B) 12

C) 19

D) 22

5) What is the sum of the coefficients when the following equation is balanced using the lowest,

whole numbered coefficients?

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

A) 8

B) 11

C) 15

D) none of these

6) Aluminum metal reacts with iron(II) sulfide to form aluminum sulfide and iron metal. What

is the stoichiometric coefficient for aluminum when the chemical equation is balanced using the

lowest, whole-number stoichiometric coefficients?

A) 1

B) 2

C) 3

D) 4

7) Calcium phosphate reacts with sulfuric acid to form calcium sulfate and phosphoric acid.

What is the stoichiometric coefficient for sulfuric acid when the chemical equation is balanced

using the lowest, whole-number stoichiometric coefficients?

A) 1

B) 2

C) 3

D) none of these

8) Given the chemical equation: N2 + 3 H2 → 2 NH3. On a microscopic level, what do the

coefficients mean?

A) 1 atom of nitrogen reacts with 3 atoms of hydrogen to give 2 atoms of ammonia.

B) 28 g of nitrogen reacts with 6 grams of hydrogen to give 34 grams of ammonia.

C) 1 mole of nitrogen reacts with 3 moles of hydrogen to give 2 moles of ammonia.

D) 1 molecule of nitrogen reacts with 3 molecules of hydrogen to give 2 molecules of ammonia.

9) Given the chemical equation: N2 + 3 H2 → 2 NH3. On a macroscopic level, what do the

coefficients mean?

A) 1 atom of nitrogen reacts with 3 atoms of hydrogen to give 2 atoms of ammonia.

B) 1 mole of nitrogen reacts with 3 moles of hydrogen to give 2 moles of ammonia.

C) 1 molecule of nitrogen reacts with 3 molecules of hydrogen to give 2 molecules of ammonia.

D) all of the above

Answer: B

Diff: 1

Topic: Section 6.1 Chemical Symbols on Different Levels

10) 1.00 mole of O2 contains the same number of molecules as

A) 0.667 mole of O3.

B) 1.00 mole of CH3CO2H.

C) 2.00 mole of CH3CH2OH.

D) all of the above.

11) 1.00 mole of O2 contains the same number of oxygen atoms as

A) 0.667 mole of O3.

B) 1.00 mole of CH3CO2H.

C) 2.00 mole of CH3CH2OH.

D) all of the above.

4

12) What is the mass of an atom of the element hydrogen?

A) 2.0 g

B) 1.0 g

C) 3.4 × 10–24 g

D) 1.7 × 10–24 g

13) What is the molar mass of aspartic acid, C4O4H7N?

A) 43 g/mol

B) 70 g/mol

C) 133 g/mol

D) 197 g/mol

14) What is the molar mass of Co(NO3)2?

A) 90 g/mol

B) 121 g/mol

C) 152 g/mol

D) 183 g/mol

15) What is the molar mass of calcium permanganate?

A) 159 g/mol

B) 199 g/mol

C) 216 g/mol

D) 278 g/mol

16) What is the molar mass of hydrogen gas?

A) 1.00 g/mol

B) 2.00 g/mol

C) 6.02 × 1023 g/mol

D) 1.20 × 1023 g/mol

17) What is the mass of a single chlorine molecule, Cl2?

5

A) 5.887 × 10-23 g

B) 1.177 × 10-22 g

C) 35.45 g

D) 70.90 g

18) What is the mass of 0.500 mol of dichlorodifluoromethane, CF2Cl2?

A) 4.14 × 10-3 g

B) 60.5 g

C) 121 g

D) 242 g

19) How many moles are in 1.50 g of ethanol, CH3CH2OH?

A) 0.0145 mol

B) 0.0326 mol

C) 30.7 mol

D) 69.0 mol

20) How many iron(II) ions, Fe2+ are there in 5.00 g of FeSO4?

A) 5.46 × 10-26 iron (II) ions

B) 1.98 × 1022 iron (II) ions

C) 1.83 × 1025 iron (II) ions

D) 4.58 × 1026 iron (II) ions

21) What is the mass of 8.50 × 1022 molecules of NH3?

A) 0.00830 g

B) 0.417 g

C) 2.40 g

D) 120 g

22) How many oxygen atoms are in 3.00 g of sodium dichromate, Na2Cr2O7?

A) 0.0801 oxygen atoms

B) 9.85 × 1020 oxygen atoms

C) 6.90 × 1021 oxygen atoms

D) 4.83 × 1022 oxygen atoms

23) What is the identity of substance X if 0.380 mol of X weighs 17.5 g?

A) NO2

B) NO3

C) N2O

D) N2O4

24) What is the molar mass of butane if 5.19 × 1016 molecules of butane weigh 5.00 μg?

A) 58.0 g/mol

B) 172 g/mol

C) 232 g/mol

D) 431 g/mol

25) What mass of dinitrogen monoxide, N2O, contains the same number of molecules as 3.00 g

of trichlorofluoromethane, CCl3F?

A) 0.106 g

B) 0.961 g

C) 1.04 g

D) 9.37 g

26) What mass of sulfur hexafluoride, SF6, has the same number of fluorine atoms as 25.0 g of

oxygen difluoride, OF2?

A) 0.901 g

B) 8.33 g

C) 22.5 g

D) 203 g

27) How many chloride ions are in 1.50 mol of aluminum chloride?

A) 3.00 chloride ions

B) 4.50 chloride ions

C) 9.03 × 1023 chloride ions

D) 2.71 × 1024 chloride ions

28) How many anions are in 0.500 g of MgBr2?

A) 1.64 × 1021 anions

B) 3.27 × 1021 anions

C) 2.22 × 1026 anions

D) 4.43 × 1026 anions

29) How many cations are in 10.0 g of sodium phosphate?

A) 3.67 × 1022 cations

B) 1.10 × 1023 cations

C) 9.87 × 1024 cations

D) 2.96 × 1025 cations

30) Which of the following has the greatest mass?

A) 6.0 × 1023 atoms of O

B) 3.0 × 1023 molecules of O2

C) 2.0 × 1023 molecules of O3

D) All have the same mass.

31) Which of the following has the greatest mass?

A) 6.02 × 1023 molecules of O2

B) 16.0 g of O2

C) 0.500 mol of O2

D) All of the above have the same mass.

32) Which of the following has the smallest mass?

A) 3.50 × 1023 molecules of I2

B) 85.0 g of Cl2

C) 2.50 mol of F2

D) 0.050 kg of Br2

33) How many moles of CuO can be produced from 0.450 mol of Cu2O in the following

reaction?

2 Cu2O(s) + O2(g) → 4 CuO(s)

A) 0.225 mol

B) 0.450 mol

C) 0.900 mol

D) 1.80 mol

34) How many moles of BCl3 are needed to produce 25.0 g of HCl(aq) in the following

reaction?

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

A) 0.229 mol

B) 0.686 mol

C) 2.06 mol

D) 4.38 mol

35) How many grams of calcium chloride are needed to produce 10.0 g of potassium chloride?

CaCl2(aq) + K2CO3(aq) → 2 KCl(aq) + CaCO3(aq)

A) 0.134 g

B) 7.44 g

C) 14.9 g

D) 29.8 g

36) Balance the chemical equation given below, and determine the number of moles of iodine

that reacts with 10.0 g of aluminum.

___ Al(s) + ___ I2(s) → ___ Al2I6(s)

A) 0.247 mol

B) 0.556 mol

C) 0.741 mol

D) 1.11 mol

37) Balance the chemical equation given below, and determine the number of grams of MgO

needed to produce 15.0 g of Fe2O3.

___ MgO(s) + ___ Fe(s) → ___ Fe2O3(s) + ___ Mg(s)

A) 0.0877 g

B) 1.26 g

C) 3.78 g

D) 11.4 g

38) Dinitrogen monoxide gas decomposes to form nitrogen gas and oxygen gas. How many

grams of oxygen are formed when 5.00 g of dinitrogen monoxide decomposes?

A) 0.550 g

B) 1.82 g

C) 3.64 g

D) 7.27 g

39) The density of ethanol, C2H5OH, is 0.789 g/mL. How many milliliters of ethanol are needed

to produce 10.0 g of CO2 according to the following chemical equation?

C2H5OH(l) + 3 O2(g) → 2 CO2(g) + 3 H2O(l)

A) 4.12 mL

B) 6.63 mL

C) 13.2 mL

D) 26.5 mL

40) When 10.0 g of calcium metal is reacted with water, 5.00 g of calcium hydroxide is

produced. Using the following balanced equation, calculate the percent yield for the reaction?

Ca(s) + 2 H2O(l) → Ca(OH)2(aq) + H2(g)

A) 13.5%

B) 27.1%

C) 50.0%

D) 92.4%

41) If the percent yield for the following reaction is 65.0%, how many grams of KClO3 are

needed to produce 42.0 g of O2?

2 KClO3(s) → 2 KCl(s) + 3 O2(g)

A) 69.7 g

B) 107 g

C) 165 g

D) 371 g

42) If the percent yield for the following reaction is 75.0%, and 45.0 g of NO2 are consumed in

the reaction, how many grams of nitric acid, HNO3(aq), are produced?

3 NO2(g) + H2O(l) → 2 HNO3(aq) + NO(g)

A) 30.8 g

B) 41.1 g

C) 54.8 g

D) 69.3 g

43) In the reaction between glucose and oxygen, 10.0 g of glucose reacts and 7.50 L of carbon

dioxide is formed. What is the percent yield if the density of CO2 is 1.26 g/L?

C6H12O6(s) + 6 O2(g) → 6 CO2(g) + 6 H2O(l)

A) 26.1%

B) 40.6%

C) 43.1%

D) 64.5%

12

44) When methane, CH4, undergoes combustion with oxygen, the usual products are carbon

dioxide and water. Carbon monoxide is formed when the limiting reactant is

A) carbon dioxide.

B) methane.

C) oxygen.

D) water.

45) 10 g of nitrogen is reacted with 5.0 g of hydrogen to produce ammonia according to the

chemical equation shown below. Which one of the following statements is false?

N2(g) + 3 H2(g) → 2 NH3(g)

A) 2.8 grams of hydrogen are left over.

B) Hydrogen is the excess reactant.

C) Nitrogen is the limiting reactant.

D) The theoretical yield of ammonia is 15 g.

46) 5.0 g of iron is reacted with 5.0 g of water according to the chemical equation shown below.

Which one of the following statements is false?

3 Fe(s) + 4 H2O(l) → Fe3O4(s) + 4 H2(g)

A) 6.91 g of Fe3O4 are produced.

B) 2.85 g of H2O are left over.

C) Mass is conserved in this reaction.

D) Water is the limiting reactant.

47) Which substance is the limiting reactant when 2.0 g of sulfur reacts with 3.0 g of oxygen and

4.0 g of sodium hydroxide according to the following chemical equation:

2 S(s) + 3 O2(g) + 4 NaOH(aq) → 2 Na2SO4(aq) + 2 H2O(l)

A) S(s)

B) O2(g)

C) NaOH (aq)

D) None of these substances is the limiting reactant.

48) When 5.00 × 1022 molecules of ammonia react with 4.00 × 1022 molecules of oxygen

according to the chemical equation shown below, how many grams of nitrogen gas are

produced?

4 NH3(g) + 3 O2(g) → 2 N2(g) + 6 H2O(g)

A) 1.16 g

B) 1.24 g

C) 2.79 g

D) 4.65 g

49) How many grams of the excess reagent are left over when 6.00 g of CS2 gas react with 10.0

g of Cl2 gas in the following reaction:

CS2(g) + 3 Cl2(g) → CCl4(l) + S2Cl2(l)

A) 2.42 g

B) 2.77 g

C) 3.58 g

D) 4.00 g

50) When silver nitrate reacts with barium chloride, silver chloride and barium nitrate are

formed. How many grams of silver chloride are formed when 10.0 g of silver nitrate reacts with

15.0 g of barium chloride?

A) 8.44 g

B) 9.40 g

C) 11.9 g

D) 18.8 g

51) When iron(III) oxide reacts with hydrochloric acid, iron(III) chloride and water are formed.

How many grams of iron(III) chloride are formed from 10.0 g of iron(III) oxide and 10.0 g of

hydrochloric acid?

A) 11.1 g

B) 14.8 g

C) 20.3 g

D) 35.1 g

52) Balance the chemical equation given below, and calculate the volume of nitrogen monoxide

gas produced when 8.00 g of ammonia is reacted with 12.0 g of oxygen at 25°C? The density of

nitrogen monoxide at 25°C is 1.23 g/L.

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

A) 7.32 L

B) 11.2 L

C) 16.5 L

D) 18.8 L

53) Molarity is defined as

A) moles of solute per liter of solution.

B) moles of solute per liter of solvent.

C) moles of solvent per liter of solution.

D) moles of solvent per liter of solvent.

54) What is the concentration of FeCl3 in a solution prepared by dissolving 10.0 g of FeCl3 in

enough water to make 275 mL of solution?

A) 2.24 × 10-4 M

B) 0.224 M

C) 4.46 M

D) 4.46 × 103 M

55) How many grams of AgNO3 are needed to make 250. mL of a solution that is 0.135 M?

A) 0.0917 g

B) 0.174 g

C) 5.73 g

D) 9.17 g

56) What volume of a 0.540 M NaOH solution contains 15.5 g of NaOH?

A) 0.209 L

B) 0.718 L

C) 1.39 L

D) 4.78 L

57) What is the concentration of NO3– ions in a solution prepared by dissolving 15.0 g of

Ca(NO3)2 in enough water to produce 300. mL of solution?

A) 0.152 M

B) 0.305 M

C) 0.403 M

D) 0.609 M

58) If the reaction of phosphate ion with water is ignored, what is the total concentration of ions

in a solution prepared by dissolving 3.00 g of K3PO4 in enough water to make 350. mL of

solution?

A) 0.0101 M

B) 0.0404 M

C) 0.162 M

D) 0.323 M

59) What is the concentration of an AlCl3 solution if 150. mL of the solution contains 250. mg of

Cl– ion?

A) 1.57 × 10-2 M

B) 3.75 × 10-2 M

C) 4.70 × 10-2 M

D) 1.41 × 10-1 M

60) Which contains the greatest number of chloride ions?

A) 25 mL of 2.0 M NaCl

B) 50 mL of 1.0 M CaCl2

C) 10 mL of 2.5 M FeCl3

D) All contain the same number of chloride ions.

61) When a 1.0 M solution of NaCl at 25°C is heated to 55°C, the

A) density decreases and the molarity decreases.

B) density decreases and the molarity increases.

C) density increases and the molarity decreases.

D) density increases and the molarity increases.

62) Which statement about diluted solutions is false? When a solution is diluted

A) the concentration of the solution decreases.

B) the molarity of the solution decreases.

C) the number of moles of solute remains unchanged.

D) the number of moles of solvent remains unchanged.

63) What is the concentration of HCl in the final solution when 65 mL of a 12 M HCl solution is

diluted with pure water to a total volume of 0.15 L?

A) 2.8 × 10-2 M

B) 5.2 M

C) 28 M

D) 5.2 × 103 M

64) How many milliliters of a 9.0 M H2SO4 solution are needed to make 0.25 L of a 3.5 M

H2SO4 solution?

A) 0.097 mL

B) 0.64 mL

C) 97 mL

D) 640 mL

65) How many mL of a 0.175 M FeCl3 solution are needed to make 250. mL of a solution that is

0.300 M in Cl– ion?

A) 0.429 mL

B) 143 mL

C) 429 mL

D) It is not possible to make a more concentrated solution from a less concentrated solution.

66) A student dissolved 3.00 g of Co(NO3)2 in enough water to make 100. mL of stock solution.

He took 4.00 mL of the solution then diluted it with water to give 275 mL of a final solution.

How many grams of NO3– ion are there in the final solution?

A) 0.0148 g

B) 0.0296 g

C) 0.0407 g

D) 0.0813 g

67) A student prepared a stock solution by dissolving 20.0 g of KOH in enough water to make

150. mL of solution. She then took 15.0 mL of the stock solution and diluted it with enough

water to make 65.0 mL of a final solution. What is the concentration of KOH for the final

solution?

A) 0.548 M

B) 0.713 M

C) 1.40 M

D) 1.82 M

68) How many milliliters of 0.260 M Na2S are needed to react with 25.00 mL of 0.315 M

AgNO3?

Na2S(aq) + 2 AgNO3(aq) → 2 NaNO3(aq) + Ag2S(s)

A) 15.1 mL

B) 30.3 mL

C) 41.3 mL

D) 60.6 mL

69) How many grams of CaCl2 are formed when 35.00 mL of 0.00237 M Ca(OH)2 reacts with

excess Cl2 gas?

2 Ca(OH)2(aq) + 2 Cl2(g) → Ca(OCl)2(aq) + CaCl2(aq) + 2 H2O(l)

A) 0.00460 g

B) 0.00921 g

C) 0.0184 g

D) 0.0217 g

70) When 125 mL of 0.500 M AgNO3 is added to 100. mL of 0.300 M NH4Cl, how many grams

of AgCl are formed?

AgNO3(aq) + NH4Cl(aq) → AgCl(s) + NH4NO3(aq)

A) 4.30 g

B) 8.96 g

C) 13.3 g

D) 25.8 g

71) How many milliliters of 0.200 M FeCl3 are needed to react with an excess of Na2S to

produce 2.75 g of Fe2S3 if the percent yield for the reaction is 65.0%?

3 Na2S(aq) + 2 FeCl3(aq) → Fe2S3(s) + 6 NaCl(aq)

A) 50.9 mL

B) 86.0 mL

C) 102 mL

D) 203 mL

72) If 100. mL of 0.100 M Na2SO4 is added to 200. mL of 0.150 M NaCl, what is the

concentration of Na+ ions in the final solution? Assume that the volumes are additive.

A) 0.133 M

B) 0.167 M

C) 0.250 M

D) 0.350 M

73) How many milliliters of 0.550 M hydriodic acid are needed to react with 25.00 mL of 0.217

M CsOH?

HI(aq) + CsOH(aq) → CsI(aq) + H2O(l)

A) 0.0158 mL

B) 0.101 mL

C) 9.86 mL

D) 63.4 mL

74) In an acid-base neutralization reaction 23.74 mL of 0.500 M potassium hydroxide reacts with

50.00 mL of sulfuric acid solution. What is the concentration of the H2SO4 solution?

A) 0.119 M

B) 0.237 M

C) 0.475 M

D) 2.11 M

75) Balance the chemical equation given below, and determine the number of milliliters of

0.0300 M phosphoric acid required to neutralize 25.00 mL of 0.0150 M calcium hydroxide.

___ Ca(OH)2(aq) + ___ H3PO4(aq) → ___ Ca3(PO4)2(s) + ___ H2O(l)

A) 1.69 mL

B) 8.33 mL

C) 12.5 mL

D) 18.8 mL

76) When 280. mL of 1.50 × 10-4 M hydrochloric acid is added to 125 mL of 1.75 × 10-4 M

Mg(OH)2, the resulting solution will be

A) acidic.

B) basic.

C) neutral.

D) It is impossible to tell from the information given.

77) Which one of the following compounds contains the smallest percent oxygen by mass?

A) CO2

B) N2O4

C) P4O10

D) SO2