If 900 J/g of heat is exchanged at boiling point of water, then what is increase in entropy

Options

(a) 900 J/mol
(b) 87.2 J/mol
(c) 43.4 J/mol
(d) Zero

Correct Answer:

43.4 J/mol

Explanation:

Heat exchanged at boiling point of water
= 900 J/g = 900 x 18 J/mol = 16200.0 J/mol.
ΔS(vap) = ΔH(vap) / T(b) = 16200/ 373 ( therefore T(b) = 273 + 100 = 373 K)
= 43.4 J/mol.