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Ch. 11 Practice Test Multiple Choice Identify the letter of the choice that best completes the statement or answers the question. ____ 1. Gay-Lussac recognized that at constant temperature and pressure, the volumes of gaseous reactants and products a. always equal 1 L. b. add up to 22.4 L. c. equal R. d. can be expressed as ratios of small whole numbers. ____ 2. When Gay-Lussac's law of combining volumes holds, which of the following can be expressed in ratios of small whole numbers? a. pressure before and pressure after reaction b. volumes of gaseous reactants and products c. Kelvin temperatures d. molar masses of products and reactants ____ 3. The law of combining volumes applies only to gas volumes a. measured at constant temperature and pressure. b. that equal 1 L. c. that equal 22.4 L. d. measured at STP. ____ 4. The reaction of two volumes of hydrogen gas with one volume of oxygen gas to produce two volumes of water vapor is an example of a. the ideal gas law. b. Graham's law of effusion. c. Gay-Lussac's law of combining volumes of gases. d. Avogadro's law. ____ 5. If 0.5 L of O2(g) reacts with H2 to produce 1 L of H2O(g), what is the volume of H2O(g) obtained from 1 L of O2(g)? a. 0.5 L c. 2 L b. 1.5 L d. Cannot be determined ____ 6. In the equation C + O2(g) CO2(g), one volume of O2 yields how many volumes of CO2? a. 1 c. 3 b. 2 d. 4 ____ 7. The principle that under similar pressures and temperatures, equal volumes of gases contain the same number of molecules is attributed to a. Berthollet. c. Avogadro. b. Proust. d. Dalton. ____ 8. Equal volumes of diatomic gases under the same conditions of temperature and pressure contain the same number of a. protons. c. molecules. b. ions. d. Dalton's "ultimate particles." ____ 9. If gas A has a molar mass greater than that of gas B and samples of each gas at identical temperatures and pressures contain equal numbers of molecules, then a. the volumes of gas A and gas B are equal. b. the volume of gas A is greater than that of gas B. c. the volume of gas B is greater than that of gas A. d. their volumes are proportional to their molar masses. ____ 10. The expression V = kn is a statement of a. the ideal gas law. c. Graham's law of effusion. b. the law of combining volumes. d. Avogadro's principle. ____ 11. Avogadro's principle led to the realization that the molecules of some substances a. could not react. c. were invisible. b. were not composed of atoms. d. were made of more than one atom. ____ 12. In the expression V = kn, n represents a. the gas constant. c. the number of moles of gas. b. Avogadro's number. d. a constant. ____ 13. According to Avogadro's law, 1 L of H2(g) and 1 L of O2(g) at the same temperature and pressure a. have the same mass. c. contain 1 mol of gas each. b. have unequal volumes. d. contain equal numbers of molecules. ____ 14. The standard molar volume of a gas at STP is a. 22.4 L. c. g-mol wt/22.4 L. b. g/22.4 L. d. 1 L. ____ 15. The standard molar volume of a gas at STP is all of the following except a. the volume occupied by 1 mol of the gas. b. 22.4 g. c. 22.4 L. d. the volume occupied by one molar mass of the gas. ____ 16. What is the volume occupied by 1 mol of water vapor at STP? a. 11.2 L c. 22.4 L b. 18.0 L d. 33.6 L ____ 17. At STP, the standard molar volume of a gas of known volume can be used to calculate the a. number of moles of gas. c. gram-molecular weight. b. rate of diffusion. d. gram-molecular volume. ____ 18. If the molecular formula of a gas is known, the molar volume is used directly in solving a. mass-mass problems. c. percentage composition problems. b. the volume of any mass of gas. d. gas volume–gas volume problems. ____ 19. Knowing the mass and volume of a gas at STP allows one to calculate the a. identity of the gas. c. condensation point of the gas. b. molar mass of the gas. d. rate of diffusion of the gas. ____ 20. What is the molar mass of gas at STP? a. density of the gas multiplied by the mass of 1 mol b. density of the gas divided by the mass of 1 mol c. density of the gas multiplied by 22.4 L d. density of the gas divided by 22.4 L ____ 21. A 1.00 L sample of a gas has a mass of 1.92 g at STP. What is the molar mass of the gas? a. 1.92 g/mol c. 22.4 g/mol b. 19.2 g/mol d. 43.0 g/mol ____ 22. A 1.00 L sample of a gas has a mass of 1.25 g at STP. What is the mass of 1 mol of this gas? a. a little less then 1.0 g c. 22.4 g b. 1.25 g d. 28.0 g ____ 23. The ideal gas law is equivalent to Boyle's law when a. Avogadro's number is reached. b. R equals zero. c. the pressure is 1 atm. d. the number of moles and the temperature are constant. ____ 24. The ideal gas law is equivalent to Avogadro's law when a. the volume is 22.4 L. b. 1 mol of a gas is present. c. the pressure and the temperature are constant. d. the volume and pressure are constant. ____ 25. The ideal gas law combines Boyle's law, Charles's law, and a. Graham's law. c. Raoult's law. b. Avogadro's law. d. Dalton's principle. ____ 26. When pressure, volume, and temperature are known, the ideal gas law can be used to calculate a. the chemical formula. c. molar amount. b. the ideal gas constant. d. compressibility. ____ 27. Which is a common unit for the ideal gas constant R? a. L·atm c. b. mol·K d. ____ 28. What is the value of the gas constant? a. c. 0.0821 0.0281 b. 0.0281 L·atm d. 0.0821 mol·K ____ 29. In the ideal gas law, what is the value that must be calculated from other measurements? a. P c. T b. V d. R ____ 30. The gas constant, R, has the value of a. c. 0.0821 0.0821 b. d. 0.0821 0.0821 ____ 31. Calculate the approximate temperature of a 0.50 mol sample of gas at 750 mm Hg and a volume of 12 L. a. –7ºC c. 15ºC b. 11ºC d. 288ºC ____ 32. A sample of gas at 25ºC has a volume of 11 L and exerts a pressure of 660 mm Hg. How many moles of gas are in the sample? a. 0.39 mol c. 9.3 mol b. 3.9 mol d. 87 mol ____ 33. What is the approximate volume of gas in a 1.50 mol sample that exerts a pressure of 0.922 atm and has a temperature of 10.0ºC? a. 13 L c. 37.8 L b. 14.2 L d. 378 L ____ 34. What pressure is exerted by 0.750 mol of a gas at a temperature of 0.00ºC and a volume of 5.00 L? a. 2.1 atm c. 4.98 atm b. 3.4 atm d. 760. atm ____ 35. A gas sample with a mass of 0.686 g is collected at 20.ºC and 722.5 mm Hg. The volume is 350. mL. What is the molar mass of the gas? a. 0.31 g/mol c. 50. g/mol b. 2.2 g/mol d. 720 g/mol ____ 36. A gas sample with a mass of 2.50 g is collected at 20.0ºC and 732.5 mm Hg. The volume is 1.28 L. What is the molar mass of the gas? a. 1.26 g/mol c. 13.7 g/mol b. 2.04 g/mol d. 48.8 g/mol ____ 37. A gas sample with a mass of 0.934 g is collected at 20.0ºC and 733.5 mm Hg. The volume is 200.0 mL. What is the molar mass of the gas? a. 116 g/mol c. 586 g/mol b. 358 g/mol d. 1464.0 g/mol ____ 38. A gas sample with a mass of 5.16 g is collected at 28ºC and 740 mm Hg. The volume is 1.00 L. What is the molar mass of the gas? a. 0.395 g/mol c. 130 g/mol b. 0.97 g/mol d. 300 g/mol ____ 39. A gas sample with a mass of 0.250 g is collected at 150.0ºC and 720. mm Hg. The volume is 85.0 mL. What is the molar mass of the gas? a. 0.0023 g/mol c. 108 g/mol b. 1.76 g/mol d. 238.0 g/mol ____ 40. A gas sample with a mass of 12.8 g exerts a pressure of 1.2 atm at 15ºC and a volume of 3.94 L. What is the molar mass of the gas? a. 19 g/mol c. 64 g/mol b. 32 g/mol d. 128 g/mol ____ 41. If n and T are constant, the ideal gas law reduces to a. Charles's law. c. Avogadro's law. b. Boyle's law. d. zero. ____ 42. If n and P are constant, the ideal gas law reduces to a. Charles's law. c. Avogadro's law. b. Boyle's law. d. zero. ____ 43. If P and T are constant, the ideal gas law reduces to a. Charles's law. c. Avogadro's law. b. Boyle's law. d. zero. ____ 44. When the ideal gas law reduces to PV = k, the expression is equivalent to a. Avogadro's law. c. Charles's law. b. Avogadro's number. d. Boyle's law. ____ 45. When the ideal gas law reduces to V = kT, the expression is equivalent to a. Boyle's law. c. Avogadro's principle. b. Charles's law. d. Gay-Lussac's law. ____ 46. When the ideal gas law reduces to V = kn, the expression is equivalent to a. Avogadro's law. c. Charles's law. b. Avogadro's number. d. Boyle's law. ____ 47. If the volume of the gaseous reactants and products in the equation 2C2H6 + 7O2 4CO2 + 6H2O are measured at 1 atm and 25ºC, the substance that could not be included in the volume relationship has what formula? a. C2H6 c. CO2 b. O2 d. H2O ____ 48. In a chemical equation, the coefficients for reactants and products that are gases indicate a. volumes at STP. c. molar mass of each substance. b. volume ratios. d. densities. ____ 49. What law helps explain the volume ratios in a chemical reaction? a. Charles's law c. Boyle's law b. Graham's law d. Gay-Lussac's law of combining volumes ____ 50. Volumes of gaseous reactants and products in a chemical reaction can be expressed as ratios of small whole numbers a. if all reactants and products are gases. b. if standard temperature and pressure are maintained. c. if constant temperature and pressure are maintained. d. if each mass equals 1 mol. ____ 51. According to Avogadro's law, in a chemical equation equal volumes of gases contain equal a. numbers of molecules. c. temperatures. b. pressures. d. masses. ____ 52. The ratios of the volumes of the gaseous reactants and products in a chemical reaction at constant temperature and pressure can be determined from the a. formulas. c. subscripts in the balanced equation. b. coefficients in the balanced equation. d. gas constant. ____ 53. In the reaction 2C + O2(g) 2CO(g), what is the volume ratio of O2 to CO? a. 1:1 c. 1:2 b. 2:1 d. 2:2 ____ 54. In the reaction 2H2(g) + O2(g) 2H2O(g), what is the volume ratio of H2 to H2O? a. 1:1 c. 4:3 b. 2:3 d. 4:6 ____ 55. In the reaction 2H2(g) + O2(g) 2H2O(g), what is the volume ratio of O2 to H2O? a. 1:1 c. 1:2 b. 2:1 d. 2:2 ____ 56. In the reaction H2(g) + Cl2(g) 2HCl, what is the volume ratio of Cl2 to HCl? a. 1:1 c. 2:1 b. 1:2 d. 2:2 ____ 57. In the reaction H2(g) + Cl2(g) 2HCl, what is the volume ratio of H2 to HCl? a. 1:1 c. 2:1 b. 1:2 d. 2:2 ____ 58. In the reaction H2(g) + Cl2(g) 2HCl, what is the volume ratio of H2 to Cl2? a. 1:1 c. 2:1 b. 1:2 d. 3:2 ____ 59. When hydrogen burns, water vapor is produced. The equation is 2H2(g) + O2(g) 2H2O(g). If 12 L of oxygen are consumed, what volume of water vapor is produced? a. 1 L c. 12 L b. 2 L d. 24 L ____ 60. For the complete combustion of 100. L of CO, the volume of oxygen required is a. 23.8 L c. 238 L b. 50.0 L d. 500. L ____ 61. Iron oxide, FeO2, is produced by the reaction Fe + O2 FeO2 (87.8 g/mol). How many grams of FeO2 can be produced from 50 L of O2 at STP? a. 19.5 g c. 50 g b. 37.8 g d. 196. g ____ 62. When carbon burns, carbon dioxide is produced by the reaction C + O2 CO2. If 14 L of CO2 are produced at STP, how many grams of carbon (atomic mass 12) were used? a. 7.5 g c. 17.5 g b. 11.2 g d. 75 g ____ 63. What determines the average kinetic energy of the molecules of any gas? a. temperature c. temperature and pressure b. pressure d. molar mass Ch. 11 Practice Test Answer Section MULTIPLE CHOICE 1. ANS: D 2. ANS: B 3. ANS: A 4. ANS: C 5. ANS: C 6. ANS: A 7. ANS: C 8. ANS: C 9. ANS: A 10. ANS: D 11. ANS: D 12. ANS: C 13. ANS: D 14. ANS: A 15. ANS: B 16. ANS: C 17. ANS: A 18. ANS: B 19. ANS: B 20. ANS: C 21. ANS: D 22. ANS: D 23. ANS: D 24. ANS: C 25. ANS: B 26. ANS: C 27. ANS: C 28. ANS: A 29. ANS: D 30. ANS: A 31. ANS: C 32. ANS: A 33. ANS: C 34. ANS: B 35. ANS: C 36. ANS: D 37. ANS: A 38. ANS: C 39. ANS: C 40. ANS: C 41. ANS: B 42. ANS: A 43. ANS: C 44. ANS: D 45. ANS: B 46. ANS: A 47. ANS: D 48. ANS: B 49. ANS: D 50. ANS: C 51. ANS: A 52. ANS: B 53. ANS: C 54. ANS: A 55. ANS: C 56. ANS: B 57. ANS: B 58. ANS: A 59. ANS: D 60. ANS: B 61. ANS: D 62. ANS: A 63. ANS: A