For a given reaction, ΔS = +69.0 J/mol∙K, and the reaction is spontaneous at temperatures above the crossover temperature, 439 K. The value of ΔH = ________ kJ/mol , assuming that ΔH and ΔS do not vary with temperature.

Question

Quizplus · Accepted Answer

The crossover temperature is where ΔG = 0, so ΔH = TΔS. Substituting the given values, ΔH = 439 K * 69.0 J/mol∙K = 30,291 J/mol = 30.3 kJ/mol.

For a Given Reaction, ΔS = +69