Which of the following statements is true concerning the reaction below? C(s,graphite)→ C(s,diamond) Substance ΔH°_f (kJ/mol)at 298 K S° (J/(mol ∙ K))at 298 K C(s,graphite) 0 5)740 C(s,diamond) 1)897 2)377 A)Under standard-state conditions,the reaction is spontaneous at all temperatures. B)Under standard-state conditions,the reaction is spontaneous only at temperatures above 564 K. C)Under standard-state conditions,the reaction is spontaneous only at temperatures below 564 K. D)Under standard-state conditions,the reaction is at equilibrium at 298 K. E)Under standard-state conditions,the reaction is not spontaneous at any temperature.

Question

Quizplus · Accepted Answer

The reaction from graphite to diamond has a positive ΔH° (endothermic) and a decrease in entropy (ΔS° is negative since the entropy of graphite is higher than that of diamond). According to the Gibbs free energy equation (ΔG° = ΔH° - TΔS°), both a positive ΔH° and a negative ΔS° make ΔG° positive at all temperatures, indicating the reaction is not spontaneous at any temperature.

Which of the Following Statements Is True Concerning the Reaction