Chapter 16, Problem 127QRT

The standard equilibrium constant is 2.1 × 10⁹ for this reaction at 25 °C

${\text{Zn}}^{2+}(\text{aq}){\text{ + 4 NH}}_{\text{3}}\text{(aq) }\rightleftharpoons {\text{ Zn(NH}}_{\text{3}}{\text{)}}_4^{2+}\text{(aq)}$

1. (a) Calculate Δ_rG° at this temperature.
2. (b) If standard-state concentrations of the reactants and products are combined, in which direction will the reaction proceed?
3. (c) Calculate Δ_rG° when [Zn(NH₃)₄²⁺] = 0.010 M, [Zn²⁺] = 0.0010 M, and [NH₃] = 3.5 × 10⁻⁴ M.