SOLVED

31) Henry’s Law constants for aqueous solutions at 25°C are 8.20 × 10-7 molal/mmHg for N2 and 1.62 × 10-6 molal/mmHg for O2. Determine the solubility of nitrogen in water under an atmospheric pressure of 760 mmHg, assuming that air is 80% N2 and 20% O2. A) 6.23 × 10-4 m B) 7.79 × 10-4 m C) 4.99 × 10-4 m D) 1.25 × 10-4 m E) 6.16 × 10-3 m 32) Henry’s Law constants for aqueous solutions at 25°C are 8.20 × 10-7 molal/mmHg for N2 and 1.62 × 10-6 molal/mmHg for O2. Determine the solubility of oxygen in water under an atmospheric pressure of 760 mmHg, assuming that air is 80% N2 and 20% O2. A) 6.2 × 10-3 m B) 2.5 × 10-4 m C) 1.3 × 10-4 m D) 5.0 × 10-4 m E) 1.2 × 10-3 m 33) Nitrogen gas has a Henry’s law constant k = 6.3 × 10-4 M/atm at 25°C. The “bends” in divers results from bubbles of N2(g) being rapidly released from body fluids when a diver ascends to the surface too quickly. Which of the following would be a good substitute for N2(g) in order to make the “bends” less severe? A) He(g), k = 3.7 × 10-4 M/atm B) Ar(g), k = 1.5 × 10-3 M/atm C) H2(g), k = 8.1 × 10-4 M/atm D) CO2(g), k = 3.4 × 10-2 M/atm 34) The solubility of CO in water at 0°C and 1 atm CO pressure is 0.0354 mg of CO in 1 mL of water. Calculate the molarity of aqueous CO solution at the normal partial pressure of CO of 0.00036 atm? A) 4.5 × 10-7 M B) 1.6 × 10-3 M C) 1.3 × 10-5 M D) 2.9 × 10-4 M E) 3.2 × 10-3 M 35) The solubility of CO in water at 0°C and 1 atm CO pressure is 0.0354 mg of CO in 1 mL of water. Calculate the molarity of aqueous CO solution at 2 atm CO pressure. A) 1.58 × 10-3 M B) 6.32 × 10-2 M C) 1.59 M D) 2.53 × 10-3 M E) 3.16 × 10-3 M 36) Which of the following is a correct statement about azeotropes? A) The components boil at distinct temperatures. B) The mixture cannot be separated by fractional distillation. C) The solution behaves as an ideal solution. D) The vapor has a different composition than the liquid. E) The solution has the same pressure as the pure solvent. 37) An azeotropic mixture is a: A) mixture of two or more substances where boiling point cannot be determined. B) solution of two or more substances present in the same amounts in the liquid phase. C) liquid mixture of two or more substances in which the vapor has the same composition as the liquid. D) liquid mixture of two or more substances linked by azide functional groups. E) solution of two or more substances that cannot be made to freeze. 38) A solution composed of 5 moles of acetone (CH3COCH3, P°A = 324 mmHg) and 5 moles of chloroform (CHCl3, P°C = 274 mmHg) has a vapor pressure of 236 mmHg. Which one of the following statements is completely true about this solution? A) The solution shows a negative deviation from Raoult’s law and thus possesses a maximum boiling azeotrope. B) The solution process is exothermic because the forces between unlike molecules are weaker than those between like molecules. C) The solution shows a positive deviation from Raoult’s law. D) The solution possesses a minimum boiling azeotrope because it shows a negative deviation from Raoult’s law. E) The solution obeys Raoult’s Law. 39) The vapor pressures of pure propyl alcohol and isopropyl alcohol are 21.0 mmHg and 45.2 mmHg, respectively, at 25°C. What is the composition of the vapor in equilibrium with a propyl alcohol – isopropyl alcohol solution in which the mole fraction of propyl alcohol is 0.250? A) xiso = 0.866, xprop = 0.134 B) xiso = 0.750, xprop = 0.250 C) xiso = 0.317, xprop = 0.683 D) xiso = 0.512, xprop = 0.488 40) What is the osmotic pressure in mmHg of 6.00 L of a 0.108 M solution at 30°C if three moles of ions are produced in aqueous solution for every mole of solute dissolved? A) 8.05 mmHg B) 3.68 × 104 mmHg C) 2.04 × 103 mmHg D) 0.0613 mmHg E) 6.13 × 103 mmHg