Name: Solutions and Chemical Equilibrium Review Worksheet Solutions Section: 1. Define the following: a. Solution: b. Saturated solution: c. Unsaturated solution: d. Supersaturated solution: e. Solubility:

2. Explain how a solution forms.

3. List the factors that affect the extent of solubility.

4. List the factors that affect the rate of solubility.

5. Assume you dissolve 45.0 g of camphor (C10H16O) in 425 mL of ethanol, C2H5OH. Calculate the molarity, molality, mole fraction, and weight percentage of camphor in this solution. The density of ethanol is 0.785 g/mL?

6. What mass of Na2CO3 must you add to 125 g of water to prepare 0.200 m Na2CO3? What is the mole fraction of Na2CO3 in the resulting solution?

7. If the molarity of commercial HCl is 12.0 M and its density is 1.18 g/cc, calculate a. the molality of the solution

b. The weight percentage of HCl in the solution

8. Concentrated sulfuric acid has a density of 1.84 g/cc and is 95 % by weight H2SO4. What is the molality of this acid? What is its molarity?

9. If 0.33 g of a gas dissolves in 1.00 L of water at a pressure of 1.75 atm, how much gas will dissolve if the pressure is raised to 10.0 atm if the temperature is held constant?

10. The solubility of a gas changes from 1.65 g/L to 0.43 g/L. If the initial pressure is 5.6 atm, what is the final pressure?

11. What are colligative properties? Name the four colligative properties. How are they affected when a solute is added (increase or decrease)?

12. 105 g of pure iodine (I2) is dissolved in 325 g of CCl4 at 65 °C. Given that the vapor pressure of CCl4 at this temperature is 531 mm Hg, what is the vapor pressure of the solution at 65 °C?

13. Urea (NH2CONH2), which is widely used in fertilizers and plastics, is highly soluble in water. If you dissolve 9.00 g of urea in 10.0 mL of water, what is the vapor pressure of the solution at 24 °C? Vapor pressure of pure water at 24 °C is 22.5 mm Hg. Assume the density of water is 1.0 g/mL.

14. A solution of glycerol, C3H5(OH)3, in 735 g of water has a boiling point of 104.4 °C at 1 atm pressure. The kb of water is 0.512 °C/m and kf of water is 1.86 °C/m. a. What is the mass of glycerol in the solution?

b. What is the mole fraction of the solute?

c. What is the freezing point depression of the solution?

d. What is the freezing point of the solution?

15. Assume a bottle of wine consists of an 11 % by weight solution of ethanol (C2H5OH) in water. If the bottle of wine is chilled to – 20 °C, will the solution begin to freeze? kf of water is 1.86 °C/m.

16. The organic compound called aluminon is used as a reagent to test for the presence of the aluminum ion in aqueous solution. A solution of 2.50 g of aluminon in 50.0 g of water freezes at -0.197 °C. What is the molar mass of aluminon. kf of water is 1.86 °C/m.

17. Arrange the following 0.25 m aqueous solutions in order of decreasing freezing point: Ethylene glycol [(C2H4(OH)2], potassium sulfate (K2SO4), aluminum chloride (AlCl3), potassium bromide (KBr).

18. An aqueous solution containing 1.00 g of bovine insulin (a protein, not ionized) per liter has an osmotic pressure of 3.1 mm Hg at 25 °C. Calculate the molar mass of bovine insulin?

Chemical Equilibrium Section: 19. a. Write the equilibrium constant expression. 2 SO2(g)

+

O2 (g)

⇄

2 SO3(g)

K = 279 M-1

b. At 1000 K the mixture contains [SO2] = 0.005 M, [O2] = 0.0019 M, [SO3] = 0.0069 M. Calculate the reaction quotient.

c. Is the reaction at equilibrium? If not, which way will the reaction proceed to reach equilibrium?

20. Hydrogen and carbon dioxide react at a high temperature to give water and carbon monoxide.

H2 (g) + CO2 (g) ⇄ H2O (g) + CO (g) a) Laboratory measurements at 986 °C show that there is 0.11 mol each of CO and H2O vapor and 0.087 mol each of H2 and CO2 at equilibrium in a 1.0 L container. Calculate the equilibrium constant for the reaction at 986 °C.

b) Suppose 0.050 mol each of H2 and CO2 are placed in a 2.0 L container. When equilibrium is achieved at 986 °C, what amounts of CO(g) and H2O(g) , in moles, would be present? (Use the value of K from part a).

21. Characterize each of the following as product or reactant favored. a) NO (g) + 1/2 O2 (g) ⇄ CO2 (g) Keq = 1.2 x 1045 b) PbF2(s)

⇄

Pb2+ (aq)

c) CO(g) + Cl2(g) d) H2O(g)

⇄

⇄

1/2

+ 2 F- (aq)

Keq = 3.7 x 10-8

COCl2 (g)

Keq = 6.5 x 1011

O2 (g) + H2 (g)

Keq = 9.1 x 10-41

22. For the equilibrium: SO2(g) + Cl2 (g) ⇄ SO2Cl2(g) Kc = 858 1/M at 303 °C. Calculate Kp for this reaction at this temperature.

23. For the reaction below, which direction would the equilibrium shift when the following stress is applied? Explain your answer. N2O3(g) ⇄ NO(g) + NO2(g) ∆H = 40.5 kJ/mol (a) Adding more N2O3(g). (b) Adding more NO2(g). (c) Removing NO (g). (d) Increasing the volume of the reaction flask. (e) Increasing the pressure on the system. (f) Lowering the temperature of the system.

24. For the reaction below, which direction would the equilibrium shift when the following stress is applied? Explain your answer. CS2(l) + 3 Cl2 (g) ⇄ S2Cl2(g) + CCl4(g) ∆H = -386 kJ (a) Increase the concentration of carbon tetrachloride.

(b) Increase the pressure on the system.

(c) Increase the temperature of the system.

(d) Increase the concentration of CS2(l).

(e) Decrease the concentration of chlorine gas.

(f) Predict the effect of decreasing the volume of the container on the equilibrium.