At what temperatures will a reaction be spontaneous if Δ_rH° = +62.4 kJ and Δ_rS° = +301 J/K? A) All temperatures below 207 K B) All temperatures above 207 K C) Temperatures between 179 K and 235 K D) The reaction will be spontaneous at any temperature E) The reaction will never be spontaneous

Question

Quizplus · Accepted Answer

To determine the temperature range for spontaneity, we use the Gibbs free energy equation: ΔG = ΔH - TΔS. A reaction is spontaneous when ΔG < 0. Given ΔH° = +62.4 kJ = 62400 J (since 1 kJ = 1000 J) and ΔS° = +301 J/K, we find the temperature at which ΔG = 0 to determine the boundary of spontaneity. Setting ΔG = 0 gives 0 = ΔH - TΔS, or T = ΔH/ΔS. Plugging in the values, T = 62400 J / 301 J/K = 207.31 K. Since ΔH is positive and ΔS is positive, the reaction becomes more spontaneous at higher temperatures. Therefore, the reaction is spontaneous at temperatures above 207 K.

At What Temperatures Will a Reaction Be Spontaneous If ΔrH°

At What Temperatures Will a Reaction Be Spontaneous If Δ_rH°