Question

It the enthalpy of vaporization of benzene is `308/ kJ mol^(-1)` at boiling point `(80^(@)C)`, calculate the entroy `(j mol^(-1) K^(-1))` in changing it from liquid to vapor.
A. 308
B. 0.873
C. 0.308
D. 873

Answer 1

Correct Answer - D
According to thermodynamics,
`Delta_(vap) S = (Delta_(vap) H)/(T_(b))`
`= (308 xx 10^(3) J mol^(-1))/((273 + 80) K)`
`= 873 K^(-1) mol^(-1)`
Note that `T_(b)` is the boiling point of benzene.