S C Kheterpal, S N Dhawan and, P N Kapil Solutions for Chapter: Thermodynamics, Exercise 10: PROBLEMS FOR PRACTICE

Calculate the entropy change of $\mathrm{n}$-hexane when one mole of it evaporates at $341.7 \mathrm{K}$ (${\mathrm{\Delta }}_{\mathrm{vap}}\mathrm{H}=29.0 \mathrm{kJ} {\mathrm{mol}}^{–1}$).

Calculate the temperature in centigrade when vaporization of water is in equilibrium at one atmospheric pressure. (Enthalpy of vaporization $=40.63 \times {10}^3 \mathrm{J} {\mathrm{mol}}^{–1}; {\mathrm{\Delta }}_{\mathrm{vap}}\mathrm{S}=108.8 \mathrm{J} {\mathrm{K}}^{–1}{\mathrm{mol}}^{–1}$).

Enthalpy change (${\mathrm{\Delta }}_{\mathrm{vap}}\mathrm{H}$) for the transition of liquid water to steam at $100° \mathrm{C}$ is $40.8 \mathrm{kJ} {\mathrm{mol}}^{–1}$. Calculate the entropy change for the process.

Ethanol boils at $78.4° \mathrm{C}$ and the standard enthalpy of vaporization of ethanol is $42.4 \mathrm{kJ} {\mathrm{mol}}^{–1}$. Calculate the entropy of vaporisation of ethanol.

What is the entropy change for conversion of one gram of ice to water at $273 \mathrm{K}$ and one atmospheric pressure (${\mathrm{\Delta }}_{\mathrm{fus}}\mathrm{H}=6.025 \mathrm{kJ} {\mathrm{mol}}^{–1}$)?

The entropy change for the vaporisation of water is $109 \mathrm{J} {\mathrm{K}}^{–1}{\mathrm{mol}}^{–1}$. Calculate the enthalpy Change for the vaporisation of water at $373 \mathrm{K}$.

Calculate the entropy change for the conversion of $2$ moles of liquid water at $373 \mathrm{K}$ to vapours, if ${\mathrm{\Delta }}_{\mathrm{vap}}\mathrm{H}$ is $37.3 \mathrm{kJ} {\mathrm{mol}}^{–1}$.

The enthalpy of vaporisation of benzene (${\mathrm{C}}_6{\mathrm{H}}_6$) is $30.8 \mathrm{kJ} {\mathrm{mol}}^{–1}$ at its boiling point ($80.1 °\mathrm{C}$). Calculate the entropy change in going from
(i) liquid to vapour and (ii) vapour to liquid at $80.1 °\mathrm{C}$.