Consider the gas-phase equilibrium
C(g) ⇌ D(g) + E(g)
For this reaction, ΔG° = −12 kJ mol⁻¹ at 298 K. Assume that ΔG° does not change significantly between 298 K and 310 K and that RT may be taken as 2.5 kJ mol⁻¹ at 298 K and 2.6 kJ mol⁻¹ at 310 K. No calculator is allowed.
(1) Using approximate, mental-math reasoning, estimate the base-10 logarithm (order of magnitude) of the equilibrium constant, K, at 298 K. Outline each step of your reasoning.
(2) Suppose a mixture initially contains only C at a total pressure of 1.0 bar. Estimate the ratio [C][D]+[E] at equilibrium at 298 K and comment on whether the reaction goes essentially to completion.
(3) Predict qualitatively how K will change when the temperature is raised to 310 K, assuming ΔG° is unchanged. Explain your reasoning quantitatively using the numerical RT values provided.