1. Write the equilibrium expression for Kp for each of the following reactions:
a. 2H2S(g) + 3O2(g) Û 2H2O(g) + 2SO2(g)
b. Zn(s) + 2HCl(g) Û ZnCl2(s) + H2(g)
2. The equilibrium constant is 0.900 at 25°C for the reaction
H2O(g) + Cl2O(g) Û 2HOCl(g),
if the pressures of the gaseous species are 200 torr for H2O, 49.8 torr for Cl2O and 21.0 torr for HOCl, is the system at equilibrium? If not, in what direction will the reaction move (to left or to right) to achieve equilibrium?
3. At 460°C, the reaction
SO2(g) + NO2(g) Û NO(g) + SO3(g)
has Kp = 85.0. What will be the equilibrium partial pressures of the four gases if a mixture of SO2 and NO2 is prepared in which they both have initial partial pressures of 0.125 atm?
4. Given SO2(g) + NO2(g) Û SO3(g) + NO(g) DH = - 32 kJ
complete the following table:
| Change |
Effect on equilibrium, Ü, Þ, no change |
| (a) increase in total volume (b) increase in temperature (c) increase in partial pressure of SO2(g) (d) increase in partial pressure of products |
_________________________ _________________________ _________________________ _________________________ |
5. A sample of orange juice has a hydronium ion concentration of 2.9 x 10-4M.
What is the pH?Is the solution acidic?
6. Calculate the pH of a 0.25 M aqueous solution of hypochlorous acid, HClO.
(Ka = 3.5 x 10-8)
7. For each of the following salts, indicate whether the aqueous solution will be acidic, basic, or neutral
(a) Fe(NO3)3
(b) Ca(CN)2
(c) NH4ClO4
(d) NH4C2H3O2 ( Ka for HC2H3O2 = 1.8 x 10-5; Ka for NH4+ = 5.6 x 10-10)
8. .Lactic acid, HLac (HC3H5O3), is a weak organic acid present in both sour milk and buttermilk.It is also a product of carbohydrate metabolism and is found in the blood after vigorous muscular activity.A buffer is prepared by dissolving 0.75 mole of lactic acid, Hlac (ka = 1.40 x 10-4), and 0.93 mole of sodium lactate, NaLac, in enough water to form 750 mL of solution.Calculate [H+] and the pH of the buffer.
9. A 50 mL sample of 0.1025 M HCN(aq) is titrated with 0.1180 M NaOH(aq).Calculate the pH of the solution at the equivalence point.Ka for HCN = 5.8 x 10-10
10. A buffer solution that is 0.99 M in HA(aq) and 0.090 M in A-(aq) has pH = 3.70.What will the [H+] and pH be after 0.10 mole NaOH(s) has been added to 1 liter of the buffer solution?Assume no change in volume takes place
11. If 25.00 mL of 0.1000M HC2H3O2 is titrated with 0.1000 M NaOH, what will be the pH(a) after 2.00 mL of NaOH has been added?
(b) after 25.00 mL of 0.1000 M NaOH has been added?