Reference Materials Gas Stoichiometry

Gas Stoichiometry 1) Which of the following gases the highest average molecular speed at room temperature? (A) He (B) Ne (C) F2 (D) Kr 2) If equal masses of CH4 and O2 are placed in a sealed container and the internal pressure is 3.0 atm, what is the partial pressure of oxygen? (A) 1.5 atm (B) 1.0 atm (C) 0.47 atm (D) 2.0 atm 3) Hydrogen gas is collected over water at 24 °C. The total pressure of the sample is 755 millimeters of mercury. At 24 °C, the vapor pressure of water is 22 millimeters of mercury. What is the partial pressure of the hydrogen gas? (A) 22 mm Hg (B) 733 mm Hg (C) 755 mm Hg (D) 777 mm Hg 4) Which of the following gases would deviate the most from ideal behavior at 10 atm and 800 ºC? (A) He (B) Ne (C) CH4 (D) UF6 5) When a sample of oxygen gas in a closed container of constant volume is heated until its absolute temperature is doubled, which of the following is also doubled? (A) The density of the gas (B) The pressure of the gas (C) The average velocity of the gas molecules (D) The number of molecules per mL 6) At constant temperature, the behavior of a sample of a real gas more closely approximates that of an ideal gas as its volume is increases because the: (A) collisions with the walls of the container become less frequent (B) average molecular speed decreases (C) average distance between molecules becomes greater (D) average molecular kinetic energy decreases 7) What is the density of helium in g/L at 760. torr and 0.0 ºC? (R*T = 22.4 L*atm/mol at 273 K) (A) 0.040 g/L (B) 0.18 g/L (C) 1.6 g/L (D) 5.6 g/L 8) An excess of Mg(s) is added to 100. mL of 0.400 M HCl. At 0 C and 1 atm, what volume of H2 gas can be obtained? Unbalanced equation: ___ Mg + HCl ➔ MgCl2 + ___ H2 (A) 22.4 mL (B) 44.8 mL (C) 224 mL (D) 448 mL 9) A flask contains 0.25 moles of SO2 (g), 0.50 moles of CH4(g), and 0.50 moles of O2 (g). The total pressure of the gases in the flask is 800 mmHg. What is the partial pressure of the SO2 (g) in the flask? (A) 600 mmHg 10) (B) 250 mmHg (C) 200 mmHg (D) 160 mmHg CS2 (l) + 3 O2 (g) → CO2 (g) + 2 SO2 (g) What volume of O2 (g) is required to react with excess CS2 (l) to produce 4.0 L of CO2 (g)? (Assume that all gases are measured at 0˚C and 1 atm) (A) 12 L (B) 22.4 L (C) 1/3 x 22.4 L (D) 3 x 22.4 L 11) According to the kinetic molecular theory, all of the following apply to a mixture of gases EXCEPT: (A) All gases travel at the same speed (B) The force of attraction between gas molecules are negligibly small (C) The gas molecules exert pressure on the wall of the container of the system (D) Compared to the volume of the system, the absolute volume of the gas molecules is negligibly small 12) An unknown gas ("A") diffuses at two times the rate of sulfur dioxide at identical conditions of pressure and temperature. What is the molar mass of gas "A"? 16.0 g/mol 32.0 g/mol 64.0 g/mol 256 g/mol Consider the three sealed identical flasks represented below, each containing 0.100 mol of the gas specified at 1 atm and 273 K for the next two questions (13 and 14). A 0.100 mol Ar B 0.100 mole Kr C 0.100 mole of Ne 13) Which is the correct comparison of the contents of the flasks? The mass of the contents of flask B is the greatest. The number of the molecules in each flask is the same The density of the contents of each flask is the same (A) I only (B) II only (D) II and III only (E) I, II, and III (C) I and II only 14) In which flask do the gas molecules have the greatest average kinetic energy? Flask A Flask B Flask C All have the same kinetic energy. Impossible to determine 15) The van der Waals equation of state for real gases is: [P + a(n/V)2] (V-nb) = nRT where the values for the a and b coefficients have been determine experimentally. Which property of the molecules in a sample is most closely related to the value of the b coefficient? (A) the size of the molecules (B) the number of the molecules (C) forces of attraction between the molecules (D) the root mean velocity of the molecule 16) Which of the below pictures best depicts the molecular motion of H2 gas molecules and Xe gas atoms in accordance with the Kinetic Molecular Theory? Assume the gases are at the same temperature and in a closed rigid container.