Question

Calculate the change in entropy (ΔS) of the following reaction at 298 K:2SO2(g) + O2(g) → 2SO3(g) Given the standard molar entropies at 298 K: ΔS°(SO2,g) = 248.2 J/Kmol ΔS°(O2,g) = 205.0 J/Kmol ΔS°(SO3,g) = 256.2 J/Kmol

Answer 1

To calculate the change in entropy  S  for the reaction, we can use the following equation:S = nS products  - nS reactants where n is the stoichiometric coefficient of each species in the balanced reaction.For this reaction, we have:S = [2  S SO3,g ] - [2  S SO2,g  + S O2,g ]Now, we can plug in the given standard molar entropies:S = [2  256.2 J/Kmol] - [2  248.2 J/Kmol + 205.0 J/Kmol]S = [512.4 J/Kmol] - [496.4 J/Kmol + 205.0 J/Kmol]S = 512.4 J/Kmol - 701.4 J/KmolS = -189.0 J/KmolSo, the change in entropy  S  for this reaction at 298 K is -189.0 J/Kmol.