Chemistry An Atoms First Approach 2nd Edition by Steven S. Zumdahl - Test Bank

Chemistry An Atoms First Approach 2nd Edition by Steven S. Zumdahl – Test Bank

 

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Sample Questions Are Posted Below

 

1. Which compound contains the highest percent by mass of hydrogen?
a. HCl
b. H2O
c. H2SO4
d. H2S
e. HF
ANSWER: b
POINTS: 1

2. Nitric acid, HNO3, contains what percent hydrogen by mass?
a. 3.25%
b. 20.0%
c. 25.4%
d. 1.60%
e. 2.22%
ANSWER: d
POINTS: 1

3. An oxide of iron has the formula Fe3O4. What mass percent of iron does it contain?
a. 0.72%
b. 28%
c. 30%
d. 70%
e. 72%
ANSWER: e
POINTS: 1

4. The mineral mimetite has the formula Pb5(AsO4)3Cl. What mass percent of oxygen does it contain?
a. 38.70 %
b. 16.34 %
c. 50.32 %
d. 12.90 %
e. 1.08 %
ANSWER: d
POINTS: 1

5. Which of the following compounds has the same percent composition by mass as styrene, C8H8?
a. Acetylene, C2H2

b. Benzene, C6H6

c. Cyclobutadiene, C4H4

d. α-ethyl naphthalene, C12H12

e. All of these
ANSWER: e
POINTS: 1

6. The molar mass of an insecticide, dibromoethane, is 187.9 g/mol. Its molecular formula is C2H4Br2. What percent by mass of carbon does dibromoethane contain?
a. 0.536%
b. 85.05%
c. 12.78%
d. 2.14%
e. 6.39%
ANSWER: c
POINTS: 1

7. Hydrocortisone valerate is an ingredient in hydrocortisone cream, prescribed for skin problems. Its molecular formula is C26H38O6. What is the percent by mass of carbon in hydrocortisone valerate?
a. 69.9%
b. 43.6%
c. 54.2%
d. 76.9%
e. 60.1%
ANSWER: a
POINTS: 1

8. Ammonium sulfate, (NH4)2SO4, contains what percent nitrogen by mass?
a. 42.4%
b. 10.6%
c. 21.2%
d. 13.7%
e. none of these
ANSWER: c
POINTS: 1

9. How many grams of potassium are in 15.0 g of K2CrO7?
a. 2.42 g
b. 0.767 g
c. 4.84 g
d. 78.2 g
e. 30.0 g
ANSWER: c
POINTS: 1

10. A substance contains 35.0 g nitrogen, 5.05 g hydrogen, and 60.0 g of oxygen. How many grams of hydrogen are there in a 151-g sample of this substance?
a. 7.62 g
b. 756 g
c. 15.2 g
d. 5.05 g
e. 29.9 g
ANSWER: a
POINTS: 1

11. A substance, A2B, has the composition by mass of 60% A and 40% B. What is the composition of AB2 by mass?
a. 40% A, 60% B
b. 50% A, 50% B
c. 27% A, 73% B
d. 33% A, 67% B
e. none of these
ANSWER: c
POINTS: 1

12. Each molecule of lycopene contains 40 atoms of carbon (plus other atoms). The mass percent of carbon in lycopene is 84.49%. What is the molar mass of lycopene?
a. 1137.2 g/mol
b. 405.9 g/mol
c. 480.4 g/mol
d. 473.4 g/mol
e. 568.6 g/mol
ANSWER: e
POINTS: 1

13. A substance contains 23.0 g sodium, 27.0 g aluminum, and 114 g fluorine. How many grams of sodium are there in a 174-g sample of the substance?
a. 7.57 g
b. 23.0 g
c. 24.4 g
d. 174 g
e. none of these
ANSWER: c
POINTS: 1

14. A compound is composed of element X and hydrogen. Analysis shows the compound to be 80% X by mass, with three times as many hydrogen atoms as X atoms per molecule. Which element is element X?
a. He
b. C
c. F
d. S
e. none of these
ANSWER: b
POINTS: 1

15. A mixture of KCl and KNO3 is 44.20% potassium by mass. The percentage of KCl in the mixture is closest to _____.
a. 40%
b. 50%
c. 60%
d. 70%
e. 80%
ANSWER: a
POINTS: 1

16. You heat 3.886 g of a mixture of Fe3O4 and FeO to form 4.095 g Fe2O3. The mass percent of FeO originally in the mixture was:
a. 94.9%.
b. 26.1%.
c. 73.9%.
d. 18.0%.
e. none of these.
ANSWER: b
POINTS: 1

17. Suppose you are given the percent by mass of the elements in a compound and you wish to determine the empirical formula. Which of the following is true?
a. You must convert percent by mass to relative numbers of atoms.
b. You must assume exactly 100.0 g of the compound.
c. You must divide all of the percent by mass numbers by the smallest percent by mass.
d. You cannot solve for the empirical formula without the molar mass.
e. At least two of the above (A-D) are true.
ANSWER: a
POINTS: 1

18. A chloride of rhenium contains 63.6% rhenium. What is the formula of this compound?
a. ReCl
b. ReCl3
c. ReCl5
d. ReCl7
e. Re2Cl3
ANSWER: b
POINTS: 1

19. A hydrocarbon (a compound consisting solely of carbon and hydrogen) is found to be 85.6% carbon by mass. What is the empirical formula for this compound?
a. CH
b. CH2
c. C2H
d. C3H
e. CH4
ANSWER: b
POINTS: 1

20. Adipic acid contains 49.32% C, 43.84% O, and 6.85% H by mass. What is the empirical formula?
a. C3H5O2
b. C3H3O4
c. C2HO3
d. C2H5O4
e. C3HO3
ANSWER: a
POINTS: 1

21. A 1.60-g sample of an oxide of bromine is converted to 2.685 g of AgBr. Calculate the empirical formula of the oxide. (molar mass for AgBr = 187.78 g/mol)
a. BrO3

b. BrO2

c. BrO
d. Br2O
e. none of these
ANSWER: a
POINTS: 1

22. The empirical formula of styrene is CH; its molar mass is 104.1 g/mol. What is the molecular formula of styrene?
a. C2H4
b. C8H8
c. C10H12
d. C6H6
e. none of these
ANSWER: b
POINTS: 1

23. A compound composed of sulfur and fluorine is found to contain 62.79% by mass of sulfur. If the molar mass of the compound is 102.13 g/mol, what is its molecular formula?
a. S3F
b. S2F4
c. SF
d. S2F
e. S2F2
ANSWER: e
POINTS: 1

24. The empirical formula of a group of compounds is CHCl. Lindane, a powerful insecticide, is a member of this group. The molar mass of lindane is 290.8 g/mol. How many atoms of carbon does a molecule of lindane contain?
a. 2
b. 3
c. 4
d. 6
e. 8
ANSWER: d
POINTS: 1

25. Vitamin C contains the elements C, H, and O. It is known to contain 40.9% C and 4.58% H by mass. The molar mass of vitamin C has been found to be about 180 g/mol. The molecular formula for vitamin C is:
a. C2H3O2.

b. C3H4O3.

c. C4H6O4.

d. C6H8O6.

e. C14H18.

ANSWER: d
POINTS: 1

26. A 0.4774-g sample of a compound known to contain only carbon, hydrogen, and oxygen was burned in oxygen to yield 0.8871 g of CO2 and 0.1816 g of H2O. What is the empirical formula of the compound?
a. CHO
b. C2H2O
c. C3H3O2
d. C6H3O2
e. C3H6O2
ANSWER: c
POINTS: 1

27. You take an aspirin tablet (a compound consisting solely of carbon, hydrogen, and oxygen) with a mass of 1.00 g, burn it in air, and collect 2.20 g of carbon dioxide and 0.400 g water. The molar mass of aspirin is between 170 and 190 g/mol. The molecular formula of aspirin is:
a. C6H8O5.

b. C9H8O4.

c. C8H10O5.

d. C10H6O4.

e. none of these.
ANSWER: b
POINTS: 1

28. Balanced chemical equations imply which of the following?
a. Numbers of molecules are conserved in chemical change.
b. Numbers of atoms are conserved in chemical change.
c. Volume is conserved in chemical change.
d. A and B
e. B and C
ANSWER: b
POINTS: 1

29. In balancing an equation, we change the _____ to make the number of atoms on each side of the equation balance.
a. formulas of compounds in the reactants
b. coefficients of compounds
c. formulas of compounds in the products
d. subscripts of compounds
e. none of these
ANSWER: b
POINTS: 1

30. What is the coefficient for water when the following equation is balanced?
As(OH)3(s) + H2SO4(aq) → As2(SO4)3(aq) + H2O(l)
a. 1
b. 2
c. 4
d. 6
e. 12
ANSWER: d
POINTS: 1

31. Which of the following equations is not balanced?
a. 4Al + 3O2 → 2Al2O3
b. C2H6 + O2 → 2CO2 + 3H2O
c. 2KClO3 → 2KCl + O2
d. 4P4 + 5S8 → 4P4S10
e. P4 + 5O2 → P4O10
ANSWER: c
POINTS: 1

32. Consider a specific chemical reaction represented by the equation aA + bB → cC + dD. In this equation the letters A, B, C, and D represent chemicals, and the letters a, b, c, and d represent coefficients in the balanced equation. How many possible values are there for the quantity “c/d”?
Reference: Ref 9-1

a. 1
b. 2
c. 3
d. 4
e. infinite
ANSWER: a
POINTS: 1

33. Consider a specific chemical reaction represented by the equation aA + bB → cC + dD. In this equation the letters A, B, C, and D represent chemicals, and the letters a, b, c, and d represent coefficients in the balanced equation. How many possible values are there for the quantity “c”?
Reference: Ref 9-1

a. 1
b. 2
c. 3
d. 4
e. infinite
ANSWER: e
POINTS: 1

34. What is the coefficient for oxygen when the following equation is balanced?
NH3(g) + O2(g) → NO2(g) + H2O(g)
a. 3
b. 6
c. 7
d. 12
e. 14
ANSWER: c
POINTS: 1

35. How many of the following statements are true concerning chemical equations?
I. Coefficients can be fractions.
II. Subscripts can be fractions.
III. Coefficients represent the relative masses of the reactants and/or products.
IV. Changing the subscripts to balance an equation can only be done once.
V. Atoms are conserved when balancing chemical equations.
a. 1
b. 2
c. 3
d. 4
e. 5
ANSWER: b
POINTS: 1

36. Determine the coefficient for O2 when the following equation is balanced in standard form (smallest whole numbers).
C6H14(g) + O2(g) → CO2(g) + H2O(g)
a. 6
b. 13
c. 14
d. 19
e. 12
ANSWER: d
POINTS: 1

37. What is the sum of the coefficients of the following equation when it is balanced using smallest whole numbers?
NaNH2 + NaNO3 → NaN3 +NaOH + NH3
a. 5
b. 6
c. 7
d. 8
e. 9
ANSWER: e
POINTS: 1

38. wPCl5 + xH2O → yPOCl3 + zHCl
The above equation is properly balanced when:
a. w = 1, x = 2, y = 2, z = 4
b. w = 2, x = 2, y = 2, z = 2
c. w = 2, x = 2, y = 2, z = 1
d. w = 1, x = 1, y = 1, z = 2
e. none of these
ANSWER: d
POINTS: 1

39. Give (in order) the correct coefficients to balance the following reaction:
H2SnCl6 + H2S → SnS2 + HCl
a. 1, 2, 1, 6
b. 1, 2, 2, 2
c. 1, 1, 1, 6
d. 6, 2, 1, 1
e. 2, 4, 2, 6
ANSWER: a
POINTS: 1

40. When the equation C8H18 + O2 → CO2 + H2O is balanced with the smallest set of integers, the sum of the coefficients is _____.
a. 4
b. 61
c. 19
d. 35
e. 44
ANSWER: b
POINTS: 1

41. Which of the following equations correctly describes the combustion of CH4 and O2 to produce water (H2O) and carbon dioxide (CO2)?
a. CH4 + O2 → CO2 + H2O
b. CH4 + O2 → CO2 + 2H2O
c. CH4 + 2O2 → CO2 + 2H2O
d. CH4 + 3O2 → 2CO2 + H2O
e. 2CH4 + 3O2 → 2CO2 + 2H2O
ANSWER: c
POINTS: 1

42. When the following equation is balanced, what is the sum of the coefficients?
Al2(SO4)3 + Ca(OH)2 → Al(OH)3 + CaSO4
a. 4
b. 9
c. 8
d. 7
e. 10
ANSWER: b
POINTS: 1

43. Potassium forms an oxide containing 1 oxygen atom for every 2 atoms of potassium. What is the coefficient of oxygen in the balanced equation for the reaction of potassium with oxygen to form this oxide?
a. 0
b. 1
c. 2
d. 3
e. 4
ANSWER: b
POINTS: 1

44. Indium reacts with chlorine to form InCl3. In the balanced equation for this reaction, the coefficient of the indium trichloride is _____.
a. 1
b. 2
c. 3
d. 4
e. 6
ANSWER: b
POINTS: 1

45. In the balanced equation for the reaction:
xP4O6(s) + yH2O(l) → zH3PO3(aq)
if x equals 2, the coefficient z equals:
a. 2
b. 4
c. 6
d. 10
e. none of these
ANSWER: e
POINTS: 1

46. The correct coefficients to balance the following reaction are, in order:
I2O5 + H2S → I2 + SO2 + H2O
a. 1, 1, 1, 1, 1
b. 1, 2, 1, 2, 1
c. 2, 4, 1, 4, 5
d. 2, 5, 2, 5, 5
e. 3, 5, 3, 5, 5
ANSWER: e
POINTS: 1

47. A reaction occurs between sodium carbonate and hydrochloric acid producing sodium chloride, carbon dioxide, and water. The correct set of coefficients, respectively, for the balanced reaction is:
a. 3 6 6 3 4
b. 8 6 5 10 5
c. 5 10 10 5 5
d. 1 2 2 1 1
e. none of these
ANSWER: d
POINTS: 1

48. A 4.54-g sample of potassium chlorate was decomposed according to the following equation:
2KClO3 → 2KCl + 3O2
How many moles of oxygen are formed?
a. 1.78 g
b. 0.0370 mol
c. 0.0247 mol
d. 0.0556 mol
e. none of these
ANSWER: d
POINTS: 1

49. A chemical reaction has the equation: 2A + B → C. Which of the following figures best illustrates a stoichiometric ratio of A and B?
I. II. III. IV.
a. I only
b. II only
c. III only
d. IV only
e. both I and IV
ANSWER: e
POINTS: 1

50. You heat 3.952 g of a mixture of Fe3O4 and FeO to form 4.162 g Fe2O3. The mass of oxygen reacted is
a. 0.210 g
b. 0.496 g
c. 1.249 g
d. 1.000 g
e. none of these
ANSWER: a
POINTS: 1

51. Reaction of methane with oxygen really proceeds in two steps:

A sample of CH4 is burned in an excess of O2 to give 4.4 moles of H2O. How many moles of CH4 were in the original sample?
a. 2.2
b. 2.9
c. 8.8
d. 1.1
e. 4.4
ANSWER: a
POINTS: 1

52. Iron is produced from its ore by the reactions:

How many moles of O2(g) are needed to produce 1.5 moles of Fe(s)?
a. 0.8 mole O2
b. 1.1 mole O2
c. 1.5 mole O2
d. 2.3 mole O2
e. 4.5 mole O2
ANSWER: b
POINTS: 1

53. What would be the g Al / mole S ratio for the product of a reaction between aluminum and sulfur?
a. 26.98 g Al / mol S
b. 53.96 g Al / mol S
c. 80.94 g Al / mol S
d. 17.99 g Al / mol S
e. 40.47 g Al / mol S
ANSWER: d
POINTS: 1

54. Sulfuric acid may be produced by the following process:
4FeS2 + 11O2 → 2Fe2O3 +8SO2
2SO2 +O2 → 2SO3
SO3 + H2O → H2SO4
How many moles of H2SO4 will be produced from 6.84 moles of FeS2?
a. 37.6
b. 6.84
c. 13.7
d. 3.42
e. 1.71
ANSWER: c
POINTS: 1

55. Consider the following reaction:

What mass of CCl4 is formed by the reaction of 4.80 g of methane with an excess of chlorine?
a. 11.5 g
b. 0.50 g
c. 738 g
d. 46.0 g
e. none of these
ANSWER: d
POINTS: 1

56. Nitric oxide, NO, is made from the oxidation of NH3, and the reaction is represented by the equation:
4NH3 + 5O2 → 4NO + 6H2O
What mass of NO can be produced from 8.34 g of NH3?
a. 4.73 g NO
b. 14.7 g NO
c. 8.34 g NO
d. 22.0 g NO
e. 18.4 g NO
ANSWER: b
POINTS: 1

57. Nitric oxide, NO, is made from the oxidation of NH3, and the reaction is represented by the equation:
4NH3 + 5O2 → 4NO + 6H2O
What mass of O2 would be required to react completely with 7.76 g of NH3?
a. 5.16 g O2
b. 11.7 g O2
c. 9.11 g O2
d. 18.2 g O2
e. 14.6 g O2
ANSWER: d
POINTS: 1

58. The Claus reactions, shown below, are used to generate elemental sulfur from hydrogen sulfide.
2H2S + 3O2 → 2SO2 + 2H2O
SO2 + 2H2S → 3S + 2H2O
How much sulfur (in grams) is produced from 12.0 grams of O2?
a. 54.1 g
b. 8.0 g
c. 12.0 g
d. 24.1 g
e. none of these
ANSWER: d
POINTS: 1

59. When 173.8 g of ethylene (C2H4) burns in oxygen to give carbon dioxide and water, how many grams of CO2 are formed?
a. 545.3 g
b. 272.7 g
c. 136.3 g
d. 6.20 g
e. 223.2 g
ANSWER: a
POINTS: 1

60. How many grams of Ca(NO3)2 can be produced by reacting excess HNO3 with 6.32 g of Ca(OH)2?
a. 7.00 g
b. 14.0 g
c. 28.0 g
d. 12.6 g
e. 6.32 g
ANSWER: b
POINTS: 1

61. The refining of aluminum from bauxite ore (which contains 50.% Al2O3 by mass) proceeds by the overall reaction 2Al2O3 + 3C → 4Al + 3CO2. How much bauxite ore is required to give the 5.0 × 1013 g of aluminum produced each year in the United States? (Assume 100% conversion.)
a. 1.3 × 1013 g
b. 5.3 × 1013 g
c. 1.9 × 1014 g
d. 7.6 × 1014 g
e. none of these
ANSWER: c
POINTS: 1

62. When rubidium metal is exposed to air, two atoms of rubidium, Rb, combine with one atom of oxygen. If 1.99 grams of rubidium is exposed to air, what will be the mass of the product in grams?
a. 17.99 g
b. 2.18 g
c. 9.99 g
d. 8.71 g
e. 4.35 g
ANSWER: b
POINTS: 1

63. For the reaction P4O10(s) + 6H2O(l) → 4H3PO4(aq), what mass of P4O10 must be consumed if 6.97 × 1023 molecules of H2O are also consumed?
a. 1.97 × 103 g P4O10
b. 54.8 g P4O10
c. 329 g P4O10
d. 3.48 g P4O10
e. 125 g P4O10
ANSWER: b
POINTS: 1

64. One commercial system removes SO2 emissions from smoke at 95.0°C by the following set of balanced reactions:
SO2 + Cl2 → SO2Cl2
SO2Cl2 + 2H2O → H2SO4 + 2HCl
H2SO4 + Ca(OH)2 → CaSO4 + 2H2O
Assuming the process is 95.0% efficient, how many grams of CaSO4 may be produced from 100. grams of SO2?
(molar masses: SO2, 64.1 g/mol; CaSO4, 136 g/mol)
a. 44.8 g
b. 47.1 g
c. 87.2 g
d. 202 g
e. 212 g
ANSWER: d
POINTS: 1

65. The following two reactions are important in the blast furnace production of iron metal from iron ore (Fe2O3):

Using these balanced reactions, how many moles of O2 are required for the production of 6.51 kg of Fe?
a. 87.4 moles
b. 38.9 moles
c. 350 moles
d. 116.6 moles
e. 4.88 moles
ANSWER: a
POINTS: 1

66. The limiting reactant in a reaction:
a. has the lowest coefficient in a balanced equation.
b. is the reactant for which you have the fewest number of moles.
c. has the lowest ratio of moles available/coefficient in the balanced equation.
d. has the lowest ratio of coefficient in the balanced equation/moles available.
e. none of these.
ANSWER: c
POINTS: 1

67. Phosphoric acid can be prepared by reaction of sulfuric acid with “phosphate rock” according to the equation:
Ca3(PO4)2 + 3H2SO4 → 3CaSO4 + 2H3PO4
Suppose the reaction is carried out starting with 113 g of Ca3(PO4)2 and 91.7 g of H2SO4. Which substance is the limiting reactant?
a. Ca3(PO4)2
b. H2SO4
c. CaSO4
d. H3PO4
e. none of these
ANSWER: b
POINTS: 1

68. Given the equation 3A + B → C + D, you react 2 moles of A with 1 mole of B. Which of the following is true?
a. A is the limiting reactant because of its higher molar mass.
b. A is the limiting reactant because you need 3 moles of A and have 2.
c. B is the limiting reactant because you have fewer moles of B than A.
d. B is the limiting reactant because 3 A molecules react with 1 B molecule.
e. Neither reactant is limiting.
ANSWER: b
POINTS: 1

69. Consider the following reaction:

What mass of CCl4 will be formed if 1.20 moles of methane react with 1.06 moles of chlorine?
a. 185 g
b. 163 g
c. 652 g
d. 40.8 g
e. 18.8 g
ANSWER: d
POINTS: 1

70. The limiting reactant in a reaction
a. is the reactant for which there is the least amount in grams
b. is the reactant which has the lowest coefficient in a balanced equation
c. is the reactant for which there is the most amount in grams
d. is the reactant for which there is the fewest number of moles
e. none of the above
ANSWER: e
POINTS: 1

71. The limiting reactant is the reactant
a. for which you have the lowest mass in grams
b. which has the lowest coefficient in the balanced equation
c. which has the lowest molar mass
d. which is left over after the reaction has gone to completion
e. none of the above
ANSWER: e
POINTS: 1

72. A chemical reaction has the equation: 2A + B→C. In which case is B the limiting reactant?

a. I
b. II
c. III
d. IV
e. none of these
ANSWER: b
POINTS: 1

73. Which of the following statements is always true concerning a reaction represented by the following balanced chemical equation?
2C2H6(g) + 7O2(g) → 6H2O(l) + 4CO2(g)
a. If we have equal masses of C2H6 and O2, there is no limiting reactant.
b. If we have an equal number of moles of C2H6 and O2, there is no limiting reactant.
c. If we have more mass of C2H6, then O2 must be limiting.
d. If we have more mass of O2, then C2H6 must be limiting.
e. None of these statements are true.
ANSWER: c
POINTS: 1

74. Equal masses (in grams) of hydrogen gas and oxygen gas are reacted to form water. Which substance is limiting?
a. Oxygen gas is limiting.
b. Hydrogen gas is limiting.
c. Water is limiting.
d. Nothing is limiting.
e. More information is needed to answer this question.
ANSWER: a
POINTS: 1

75. Suppose the reaction Ca3(PO4)2 + 3H2SO4 → 3CaSO4 + 2H3PO4 is carried out starting with 155 g of Ca3(PO4)2
and 81.3 g of H2SO4. How much phosphoric acid will be produced?
a. 81.2 g
b. 54.1 g
c. 236.3 g
d. 121.8 g
e. 97.9 g
ANSWER: b
POINTS: 1

76. Phosphorus, P4, can be prepared from calcium phosphate by the reaction
3330 g 1670 g 685 g
2Ca3(PO4)2 + 6SiO2 + 10C → 6CaSiO3 + P4 + 10CO

310 g/mol 60.1 g/mol 12.0 g/mol

The molar mass for each reactant is shown below the reactant, and the mass of each reactant for this problem is given above. Which reactant is the limiting reagent?
a. C
b. SiO2
c. Ca3(PO4)2
d. P4
e. More information is needed.
ANSWER: b
POINTS: 1

77. SO2 reacts with H2S as follows:
2H2S + SO2 → 3S + 2H2O
When 7.50 g of H2S reacts with 12.75 g of SO2, which statement applies?
a. 6.38 g of sulfur are formed.
b. 10.6 g of sulfur are formed.
c. 0.0216 moles of H2S remain.
d. 1.13 g of H2S remain.
e. SO2 is the limiting reagent.
ANSWER: b
POINTS: 1

78. How many grams of H2O will be formed when 32.0 g H2 is mixed with 77.0 g of O2 and allowed to react to form water?
a. 86.7 g
b. 286 g
c. 43.4 g
d. 21.7 g
e. 144 g
ANSWER: a
POINTS: 1

79. A 15-g sample of lithium is reacted with 15 g of fluorine to form lithium fluoride:
2Li + F2 → 2LiF. After the reaction is complete, what will be present?
a. 2.16 moles lithium fluoride only
b. 0.789 moles lithium fluoride only
c. 2.16 moles lithium fluoride and 0.395 moles fluorine
d. 0.789 moles lithium fluoride and 1.37 moles lithium
e. none of these
ANSWER: d
POINTS: 1

80. Consider the fermentation reaction of glucose:

A 1.00-mole sample of C6H12O6 was placed in a vat with 100 g of yeast. If 62.2 grams of C2H5OH was obtained, what was the percent yield of C2H5OH?
a. 67.5%
b. 33.8%
c. 100%
d. 62.2%
e. none of these
ANSWER: a
POINTS: 1

81. A 5.95-g sample of AgNO3 is reacted with BaCl2 according to the equation

to give 4.43 g of AgCl. What is the percent yield of AgCl?
a. 62.8%
b. 74.5%
c. 44.1%
d. 88.2%
e. 100%
ANSWER: d
POINTS: 1

82. The reaction of 11.9 g of CHCl3 with excess chlorine produced 11.9 g of CCl4, carbon tetrachloride:

What is the percent yield?
a. 100%
b. 38.7%
c. 77.4%
d. 100%
e. 51.6%
ANSWER: c
POINTS: 1

83. When 20.0 g C2H6 and 60.0 g O2 react to form CO2 and H2O, how many grams of water are formed?
a. 14.5 g
b. 18.0 g
c. 58.0 g
d. 20.0 g
e. none of these
ANSWER: e
POINTS: 1

84. The following equation describes the oxidation of ethanol to acetic acid by potassium permanganate:

5.00 g of ethanol and an excess of aqueous KMnO4 are reacted, and 5.99 g of HC2H3O2 result. What is the percent yield?
a. 100%
b. 91.9%
c. 30.6%
d. 8.1%
e. 5.99 g HC2H3O2 is impossible since it represents more than 100% yield.
ANSWER: b
POINTS: 1

85. Consider the following reaction:
2A + B → 3C + D
3.0 mol A and 2.0 mol B react to form 4.0 mol C. What is the percent yield of this reaction?
a. 50%
b. 67%
c. 75%
d. 89%
e. 100%
ANSWER: d
POINTS: 1

86. If 33.0 g of O2 are mixed with 33.0 g of H2 and the mixture is ignited, what mass of water is produced?
a. 33.0 g
b. 37.2 g
c. 58.6 g
d. 18.6 g
e. 66.0 g
ANSWER: b
POINTS: 1

87. Nitric oxide, NO, is made from the oxidation of NH3, and the reaction is represented by the equation:
4NH3 + 5O2 → 4NO + 6H2O
A 9.3-g sample of NH3 gives 12.0 g of NO. The percent yield of NO is _____.
a. 78%
b. 59%
c. 46%
d. 73%
e. 18%
ANSWER: d
POINTS: 1

88. For the reaction N2(g) + 2H2(g) → N2H4(l), if the percent yield for this reaction is 77.0%, what is the actual mass of hydrazine (N2H4) produced when 25.19 g of nitrogen reacts with 4.75 g of hydrogen?
a. 37.4 g N2H4
b. 22.2 g N2H4
c. 29.9 g N2H4
d. 28.8 g N2H4
e. 29.0 g N2H4
ANSWER: b
POINTS: 1

89. Ammonia can be made by reaction of water with magnesium nitride as shown by the following unbalanced equation:
Mg3N2(s) + H2O(l) → Mg(OH)2(s) + NH3(g)
If this process is 77% efficient, what mass of ammonia can be prepared from 24.0 kg magnesium nitride?
a. 3.1 kg NH3
b. 8.1 kg NH3
c. 6.2 kg NH3
d. 4.0 kg NH3
e. 19 kg NH3
ANSWER: c
POINTS: 1

90. What volume of carbon dioxide measured at STP will be formed by the reaction of 1.43 mol of oxygen with 0.900 mol of ethyl alcohol, CH3CH2OH?
a. 40.3 mL
b. 21.4 L
c. 32.0 L
d. 48.0 L
e. 0.953 L
ANSWER: b
POINTS: 1

91. A mixture of KCl and KClO3 weighing 1.37 grams was heated; the dry O2 generated occupied 143 mL at STP. What percent of the original mixture was KClO3, which decomposes as follows:

a. 38.1%
b. 57.1%
c. 85.7%
d. 10.4%
e. 23.2%
ANSWER: a
POINTS: 1

92. One way to isolate metals from their ores is to react the metal oxide with carbon as shown in the following reaction:
2MO(s) + C(s) → 2M(s) + CO2(g)
If 33.21 g of a metal oxide reacted with excess carbon and 4.26 L of CO2 formed at 100ºC and 1.50 atm, what is the identity of the metal?
a. Hg
b. Mg
c. Cu
d. Cd
e. Cr
ANSWER: c
POINTS: 1

93. Oxygen gas, generated by the reaction is collected over water at 27°C in a 1.04-L vessel at a total pressure of 1.00 atm. (The vapor pressure of H2O at 27°C is 26.0 torr.) How many moles of KClO3 were consumed in the reaction?
a. 0.0408 moles
b. 0.061 moles
c. 0.0272 moles
d. 0.0291 moles
e. 1.00 moles
ANSWER: c
POINTS: 1

94. The molecular formula always represents the total number of atoms of each element present in a compound.
a. True
b. False
ANSWER: True
POINTS: 1

95. When balancing a chemical equation, it is generally best to start with the least complicated molecules.
a. True
b. False
ANSWER: False
POINTS: 1

96. To balance a chemical equation, the coefficients must not be changed.
a. True
b. False
ANSWER: False
POINTS: 1

97. Given the equation 3A + B → C + D, you react 1 mole of A with 3 moles of B.
True or false: A is the limiting reactant because you have fewer moles of A than B.
a. True
b. False
ANSWER: False
POINTS: 1

98. The reactant with the highest molar mass is always the limiting reactant.
a. True
b. False
ANSWER: False
POINTS: 1

99. The reactant which, when used up completely, can produce the least amount of product, is the limiting reactant.
a. True
b. False
ANSWER: True
POINTS: 1

100. Vitamin B12, cyanocobalamin, is essential for human nutrition. It’s concentrated in animal tissue but not in higher plants. People who abstain completely from animal products may develop anemia, so cyanocobalamin is used in vitamin supplements. It contains 4.35% cobalt by mass. Calculate the molar mass of cyanocobalamin assuming there is one cobalt per molecule.
ANSWER: 1355 g/mol
POINTS: 1

101. Give the empirical formula for the following compounds:
a)

b)

c)

d)

ANSWER: a) CH b) CH2 c) CH2O d) C3H5O
POINTS: 1

102. The hormone epinephrine is released in the human body during stress and increases the body’s metabolic rate. Epinephrine, like many biochemical compounds, is composed of carbon, hydrogen, oxygen, and nitrogen. The percentage composition of the hormone is 59.0% C, 7.15% H, 26.2% O, and 7.65% N. Determine the empirical formula.
ANSWER: C9H13NO3
POINTS: 1

103. In order to determine the molecular formula from the empirical formula, we must know the __________.

ANSWER: molar mass
POINTS: 1

104. The characteristic odor of pineapple is due to ethyl butanoate, a compound containing carbon, hydrogen, and oxygen. Combustion of 2.78 g of ethyl butanoate leads to formation of 6.32 g of CO2 and 2.58 g of H2O. The properties of the compound suggest that the molar mass should be between 100 and 150 g/mol. What is the molecular formula?
ANSWER: C6H12O2
POINTS: 1

105. One of the major commercial uses of sulfuric acid is in the production of phosphoric acid and calcium sulfate. The phosphoric acid is used for fertilizer. The reaction is Ca3(PO4)2 + 3H2SO4 → 3CaSO4 + 2H3PO4. What mass of concentrated H2SO4 (98% by mass) must be used to react completely with 100.00 g of calcium phosphate?
ANSWER: 97 g H2SO4
POINTS: 1

106. In a metallurgical process the mineral pyrite, FeS2, is roasted in air:
FeS2 + O2 → Fe2O3 + SO2
The SO2 is then converted into H2SO4 in the following reactions:
2SO2 + O2 → 2SO3
SO3 + H2SO4 → H2S2O7
H2S2O7 + H2O → 2H2SO4
Assuming the mineral is 24.0% FeS2 and the remainder is inert, what mass of H2SO4 is produced if 155 g of the mineral is used?
ANSWER: 60.8 g H2SO4
POINTS: 1

107. The percent yield is a ratio of the ____________ yield to the _____________ yield, multiplied by 100%.

ANSWER: actual, theoretical
POINTS: 1

108. Naturally occurring copper exists in two isotopic forms: 63Cu and 65Cu. The atomic mass of copper is 63.55 amu. What is the approximate natural abundance of 63Cu?
a. 63%
b. 90%
c. 70%
d. 50%
e. 30%
ANSWER: c
POINTS: 1

109. The average mass of a carbon atom is 12.011. Assuming you were able to pick up only one carbon unit, the chances that you would randomly get one with a mass of 12.011 is _____.
a. 0%
b. 0.011%
c. about 12%
d. 12.011%
e. greater than 50%
ANSWER: a
POINTS: 1

110. Iron is biologically important in the transport of oxygen by red blood cells from the lungs to the various organs of the body. In the blood of an adult human, there are approximately 2.66 × 1013 red blood cells with a total of 2.90 g of iron. On the average, how many iron atoms are present in each red blood cell? (molar mass Fe = 55.85 g/mol)
a. 8.51 × 10–10
b. 1.18 × 109
c. 3.13 × 1022
d. 2.66 × 1013
e. 6.09 × 10–2
ANSWER: b
POINTS: 1

111. How many moles of hydrogen sulfide are contained in a 39.3-g sample of this gas?
a. 0.867 mol
b. 1.15 mol
c. 73.4 mol
d. 19.5 mol
e. 2.31 mol
ANSWER: b
POINTS: 1

112. Roundup, an herbicide manufactured by Monsanto, has the formula C3H8NO5P. How many moles of molecules are there in a 213.3-g sample of Roundup?
a. 0.7927
b. 1.544
c. 1.262
d. 11.85
e. none of these
ANSWER: c
POINTS: 1

113. What is the mass of a 7.508-mol sample of sodium hydroxide?
a. 40.00 g
b. 300.3 g
c. 180.2 g
d. 5.327 g
e. 0.1877 g
ANSWER: b
POINTS: 1

114. A sample of ammonia has a mass of 84.7 g. How many molecules are in this sample?
a. 4.97 molecules
b. 5.10 × 1025 molecules
c. 1.21 × 1023 molecules
d. 2.99 × 1024 molecules
e. 1.68 × 10–15 molecules
ANSWER: d
POINTS: 1

115. A given sample of a xenon fluoride compound contains molecules of a single type XeFn, where n is some whole number. Given that 8.86 × 1020 molecules of XeFn weigh 0.361 g, calculate n.
a. 1
b. 4
c. 2
d. 3
e. 6
ANSWER: e
POINTS: 1

116. How many atoms of hydrogen are present in 6.43 g of ammonia?
a. 2.27 × 1023
b. 1.28 × 1024
c. 1.16 × 1025
d. 6.82 × 1023
e. 9.41 × 1019
ANSWER: d
POINTS: 1

117. One molecule of a compound weighs 3.13 × 10–22 g. The molar mass of this compound is:
a. 1.92 g/mol.
b. 531 g/mol.
c. 531 g/mol.
d. 188 g/mol.
e. none of these.
ANSWER: d
POINTS: 1

118. What is the molar mass of ethanol (C2H5OH)?
a. 45.06 g/mol
b. 34.06 g/mol
c. 46.07 g/mol
d. 30.03 g/mol
e. 105.03 g/mol
ANSWER: c
POINTS: 1

119. What is the molar mass of cryolite (Na3AlF6)?
a. 209.9 g/mol
b. 185.3 g/mol
c. 210.0 g/mol
d. 104.2 g/mol
e. 68.97 g/mol
ANSWER: c
POINTS: 1

120. Calculate the molar mass of magnesium sulfite.
a. 120.38 g/mol
b. 88.38 g/mol
c. 128.69 g/mol
d. 288.83 g/mol
e. 104.38 g/mol
ANSWER: e
POINTS: 1

121. The molar mass of the compound formed by potassium and sulfur is _____.
a. 110.3 g/mol
b. 103.2 g/mol
c. 71.2 g/mol
d. 135.3 g/mol
e. 149.4 g/mol
ANSWER: a
POINTS: 1

122. How many oxygen atoms are there in one formula unit of Ca3(PO4)2?
a. 2
b. 4
c. 6
d. 8
e. none of these
ANSWER: d
POINTS: 1

123. How many oxygen atoms are there in 3 formula units of Al(NO3)3?
a. 9
b. 15
c. 27
d. 14
e. 30
ANSWER: c
POINTS: 1

124. How many of the following are true concerning balanced chemical equations?
I. The number of molecules is conserved.
II. The coefficients for the reactants tell you how much of each reactant you are given.
III. Atoms are neither created nor destroyed.
IV. The coefficients indicate the mass ratios of the substances used.
V. The sum of the coefficients on the reactant side equals the sum of the coefficients on the product side.
a. 1
b. 2
c. 3
d. 4
e. 5
ANSWER: a
POINTS: 1

125. Naturally occurring iron contains 5.82% , 91.66% , 2.19% , and 0.33%. The respective atomic masses are 53.940 amu, 55.935 amu, 56.935 amu, and 57.933 amu. Calculate the average atomic mass of iron.
ANSWER: 55.85 amu
POINTS: 1

126. In a chemical equation, the _________ are written on the left side of the arrow, and the _________ are written on the right side of the arrow.
ANSWER:
reactants, products
POINTS: 1

127. The __________ in a balanced equation represent numbers of molecules.
ANSWER: coefficients
POINTS: 1