Question

Calculate the standard entropy change for the reaction

P4(g)+5O2(g)→P4O10(s)

using the data from the following table:

Substance	ΔH∘f (kJ/mol)	ΔG∘f (kJ/mol)	S∘ [J/(K⋅mol)]
P4(g)	58.9	24.5	279.9
O2(g)	0	0	205.0
P4O10(s)	−2984	−2698	228.9

Answer 1

Solution :-

Formula to calculate the entropy chnage of the reaction using the standard entropy values is as follows

Delta S rxn = Sum delta S product - Sum of delta S reactant

delta S rxn = [1*P4O10(s)] - [(1*P4(g))+(5*O2(g))]

now lets put the entropy (S) values in the formula

Delta S rxn = [1*228.9] - [(1*279)+(5*205.0)]

Delta S rxn = -1075.1 J/ K

Thereefore the standard entropy change of the reaction = -1075.1 J/K

Answer 2