The enthalpy of vaporisation of liquid diethly ether `-(C_2H_5)_2O,` is `26.0kJmol(-1)` at its boiling point `(35.0^@C)`. Calculate `DeltaS` for conversion of : (a) liquid to vapour, and (b) vapour to liquid at `35^@C`.

Explanation

(a) `DeltaS_(vap)=(DeltaH_(vap))/T=(26xx10^(3))/308`
`=+84.41 JK^(-1) mol^(-1)`
(b) `DeltaS_(cond)=(DeltaH_(cond.))/T=-(26xx10^(3))/308( :' H_(cond)=-26 kJ)`
`=-84.41 KJ^(-1)mol^(-1)`