Question

1. Which of the following conditions defines a non-spontaneous oxidation-reduction reaction?

E° +                     ΔG° -                   K_eq <1

E° -                      ΔG° -                   K_eq <1

E° +                     ΔG°+                   K_eq >1

E° +                     ΔG°-                    K_eq >1

E° -                      ΔG° +                  K_eq <1

2. What information can be obtained from the Figure below?

The equivalence point occurs at pH = 7.0 but the pK_a is not known from the graph.

Both the pOH and the pK_b cannot be calculated from the graph.

The equivalence point occurs at pOH = 10 and the pK_b = 6.0

The equivalence point occurs at pH = 8.0 and the pK_a = 4.0

3.

At a certain temperature, K_p = 4.5 x 10³ for the reaction:

                2H₂S(g) ⇌ 2H₂(g) + S₂(g)

If P[H₂S] = 0.0050 atm, P[H₂] = 0.50 atm, and P[S₂] = 0.75 atm, then

Q_p > K_p and the reaction will shift toward reactants.

Q_p < K_p and the reaction will shift toward reactants

Q_p = K_p and the reaction is at equilibrium.

Q_p > K_p and the reaction will shift toward products.

Q_p < K_p and the reaction will shift toward products.

4.

For the following electrochemical cell:

                  2 Al(s) + 3 Mn²⁺(aq) ⟶ 2 Al³⁺(aq) + 3 Mn(s)       E° = 0.48 V

what is the value of E (at 298 K) when [Al³⁺] = 1.0 M and [ Mn²⁺] = 0.050 M?

5.

Data representing initial concentrations and initial rates for the following reaction are given below. Choose the correct rate expression.

                                                  2ClO₂(aq) + 2OH^-(aq) → ClO₃^-(aq) + ClO₂^-(aq) + H₂O(l)

      Exp. No.                          [ClO2]o (M)       [OH-]o (M)      Initial Rate (M/s)

                1                                         0.060                 0.030               0.0248

                2                                         0.020                 0.030               0.00276

                3                                         0.020                 0.090               0.00828

6.

A galvanic cell is constructed using the following half reactions:

                                  Sn²⁺+ 2 e^- ⟶ Sn(s)             -0.14 V

                                  Cu²⁺ + 2 e^- ⟶ Cu (s)           +0.34 V

Based on their reduction half-potentials, which metal will likely serve as the cathode and what would be the E°_cell for the cell?

-0.48 V; Sn        

+0.48 V; Cu  

-0.20 V; Sn

+0.20 V; Sn        

+0.20 V; Cu   

Answer 1