Calculate the standard entropy change for the reaction.

Question

PCl5(g)      PCl3(g) + Cl2(g)

Compound	S° (J mol-1 K-1)
PCl5 (g)	352.7
PCl3 (g)	311.7
Cl2 (g)	223.0

Answer 1

PCl5(g) ==> PCl3(g) + Cl2(g)

352.7...........311.7........223.0

∆S_ºrxn = ∑products - ∑reactants

∆S_ºrxn = (311.7 + 223.0) - (352.7)

∆S_ºrxn = 534.7 - 352.7

∆S_ºrxn = 182 J/mol K