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1. Which of the following would have the highest average speed if they were all at the same temperature? a. CO2 b. Ar c. Cl2 d. Xe e. Ne 2. Which of the following samples would behave most ideally under the conditions stated? a. CO at 250 atm b. N2 (B.P.= –200 °C) at –190 °C c. Br2 (B.P. = 59 °C) at 150 °C d. Xe at 400 atm e. Not enough information to determine. 3. A sealed vessel contains 12.0 L of a gas at 10.0 atm and 35°C. What volume would the gas have at STP? a. 14.3 L b. 94 L c. 701 L d. 106 L e. 22.4 L 4. Using the graph below (all 4 gas samples are at STP), determine which of the gases has the largest molar mass. a. A b. B c. C d. D e. They all have the same density at STP. 5. Using the graph below, determine the gas that has the highest density at STP. a. A b. B c. C d. D e. They all have the same density at STP. 6. How many molecules of O2 are present in a 3.9 L flask that contains only oxygen at STP? a. 1.05 x 1023 O2 molecules b. 1.74 x 1023 O2 molecules c. 5.74 x 1023 O2 molecules d. 3.46 x 1024 O2 molecules e. 9.60 x 1022 O2 molecules 7. What pressure would the gas mixture in a 5.0 L steel tank exert if it contained 4.5 g of Ar and 3.2 g of He at 225°C? a. 7.5 atm b. 63 atm c. 6.6 atm d. 4.5 atm e. 0.90 atm 8. Which of the following gases has the largest molar mass if all of the densities given are at STP? a. A, dA = 3.5 g/L b. B, dB = 1.2 g/L c. C, dC = 2.6 g/L d. D2, dD2 = 2.9 g/L e. E3, dE3 = 1.7 g/L 9. Place the following gases in order of increasing density at STP. Ar Ne Cl2 CO2 a. Ne < Ar < Cl2 < CO2 b. Cl2 < CO2 < Ar < Ne c. Ne < Ar < CO2 < Cl2 d. CO2 < Cl2 < Ar < Ne e. Ar < CO2 < Ne < Cl2 10. Which of the following would have the highest pressure if placed in identical containers (all identical in size and T)? a. 32 g O2 b. 32 g N2 c. 16 g He d. 16 g Ar 11. How many gaseous molecules of methane (CH4) are present in a 2000. mL container under STP conditions? a. 1.43 x 1023 molecules of CH4 b. 8.92 x 1023 molecules of CH4 c. 5.37 x 1022 molecules of CH4 d. 4.92 x 1025 molecules of CH4 e. 8.60 x 1023 molecules of CH4 12. What volume of CO2 gas is obtained when 117.5 g of dry ice (solid CO2) is placed inside a balloon and allowed to warm to room temperature (298 K). The atmospheric pressure during the experiment is 720.9 Torr. a. 26.2 L b. 37.4 L c. 59.8 L d. 118 L e. 68.9 L 13. Which of the following would cause the pressure of 1 mol of an ideal gas to decrease by a factor of 2? a. Increasing the absolute temperature by a factor of 2. (assume constant volume) b. Decreasing the volume of the container by a factor of 2. (assume constant T) c. Increasing the volume of the container by a factor of 2. (assume constant T) d. Reducing the temperature from 500. °C to 250. °C. (assume constant volume) e. None of the above. 14. Which of the following would cause the volume of 1 mole of an ideal gas to increase by a factor of 4? a. Increasing the temperature from 25 °C to 100 °C at constant pressure. b. Decreasing the pressure from 8 atm to 4 atm at constant temperature. c. Decreasing the absolute temperature by a factor of 4 at constant pressure. d. Decreasing the pressure from 4 to 2 atm, while increasing the absolute temperature by a factor of 2. e. None of the above will cause the volume to increase by a factor of 4. 15. Calculate the volume of a sample of carbon dioxide that is at ‐27 °C and 0.378 atm if it occupies 4.57 L at 398 K and 780. Torr. a. 5.83 L b. 1.04 L c. 7.67 L d. 12.4 L e. 2.89 L 16. What temperature must a sample of N2 (initially at 50.0 °C, 785 Torr, and 2.8 L) be heated to in order to reach a volume of 4.6 L at 1.9 atm? a. 102 K b. 199 K c. 1070 K d. 370 K e. 976 K 17. Determine the partial pressure (in atm) of Ar in a gas mixture of Ar, F2 and CO2, if the total pressure in the 1.0 L container is 4.98 x 103 Torr. The mole fraction of F2 = 0.33 and CO2 = 0.17 in this mixture. a. 2.2 atm b. 6.6 atm c. 1.1 atm d. 3.3 atm e. 8.5 atm 18. What is the total pressure of a gas mixture that contains N2, O2, and He, where the mole fraction of He is 0.10 and the partial pressure of helium in the mixture is 0.33 atm? a. 0.33 atm b. 0.99 atm c. 0.66 atm d. 3.3 atm e. 9.9 atm 19. How many grams of H2O can form when 39.9 g of CaSiO3 and 6.3 L of HF react at STP? CaSiO3(s) + 6HF(g) → CaF2(s) + SiF4(g) + 3H2O(l) [mol wt of CaSiO3 is 116.1g/mol] a. 18.6 g H2O b. 2.81 g H2O c. 2.53 g H2O d. 34.3 g H2O e. 5.06 g H2O 20. Determine the mass of water formed when 21.3 L of NH3 (at 1.5 atm) is reacted with 12.5 L of CO2 (at 2.2 atm)? Assume that all compounds have a temperature of 300 K. 2NH3 (g) + CO2 (g) → NH2CONH2 (aq) + H2O (l) a. 12 g H2O b. 20. g H2O c. 23 g H2O d. 57 g H2O e. None of the above. 21. Consider an apparatus that consists of two glass bulbs connected by a valve that is initially closed (assume that the valve has negligible volume). One bulb contains Ar with a pressure of 4.5 atm and a volume of 2.1 L. The other bulb contains Cl2 with a volume of 4.4 L and a pressure of 1.5 atm. What is the final pressure when the valve is opened and the gases mix? Assume there is no reaction between the gases. a. 3.0 atm b. 6.0 atm c. 3.3 atm d. 2.5 atm e. 2.3 atm 22. Calculate the volume of nitrogen dioxide formed at 725 Torr and 35.5 °C by the reaction of 9.78 cm3 of copper (d = 8.95 g/cm3) with 278.0 mL of nitric acid (d =1.42g/cm3, 68.0% HNO3 by mass). Cu (s) + 4HNO3 (aq) → Cu(NO3)2 (aq) + 2NO2 (g) + 2H2O (l) a. 73.0 L b. 130. L c. 12.4 L d. 56.5 L e. 47.7 L