Question

Calculate the change in entropy (in J/K) for the following reaction at 298 K: 2CH3OH (l) + 3O2 (g) → 2CO2 (g) + 4H2O (l) Given the following standard entropy values (in J/K): CH3OH (l): 126.6, O2 (g): 205.0, CO2 (g): 213.6, H2O (l): 69.9

Answer 1

To calculate the change in entropy  S  for the reaction, we need to find the difference between the total entropy of the products and the total entropy of the reactants.S = S products  - S reactants First, let's find the total entropy of the reactants:2CH3OH  l : 2 * 126.6 J/K = 253.2 J/K3O2  g : 3 * 205.0 J/K = 615.0 J/KTotal entropy of reactants = 253.2 J/K + 615.0 J/K = 868.2 J/KNow, let's find the total entropy of the products:2CO2  g : 2 * 213.6 J/K = 427.2 J/K4H2O  l : 4 * 69.9 J/K = 279.6 J/KTotal entropy of products = 427.2 J/K + 279.6 J/K = 706.8 J/KFinally, let's calculate the change in entropy  S :S = S products  - S reactants  = 706.8 J/K - 868.2 J/K = -161.4 J/KThe change in entropy for the reaction is -161.4 J/K.