Assignment:
Q1. Calculate the molar solubility of Mg(OII)_2 in a solution with a pH of 12.8 (K_op of Mg(OH)^2 is 1.2 * 10^-11
Q2. For a reaction to be spontaneous at any temperature, which one of the following is true:
a) [delta] H is positive and [delta] S is positive
b) [delta] H is positive and [delta] S is negative
c) [delta] H is negative and [delta] S is negative
Q3. Which one of the following solutions can act as a buffer?
a) Nat/HI
b) NaOH/NaCI
c) NaCN/HCN
d) NAI/CH_3COONa
Q4. A student is asked to prepare a buffer solution at pH = 3.6, which one of the following weak acids should be used?
a) NH_4CI (K_b = 1.8 * 10^-5 for NH_4OH
b) HA (K_a = 2.7 * 10 ^-4)
c) HB (K_a = 1.5 * 10^-9)
d) HC (K_a = 5.3 * 10^-13)
Q5. Which one of the following statements is false?
In the equilibrium Mg(OH)_ (s) ---Mg^2+ (aq) + 2OH(aq)
a) The reaction moves forward when adding in acid
b) The reaction moves backward when adding in solid NaCl
c) The reaction moves backward when adding in solid MgCl^2
d) The reaction moves forward when adding in water
Q6. Acetic acid, CH_3COOH is a weak acid (K_a - 1.8 * 10 ^-5)
a) Solution A is 100ml of 0.10M acetic acid
b) Solution B is prepared by adding 0.0050 mol solid NaOH to Solution A
c) Solution C is prepared by adding 0.010 mol solid NaOH to Solution A
d) Solution D is made by adding 0.0150 mil solid NaOH into Solution A
e) Calculate the pH for each of the solutions, A,B,C, and D