One mole of a gas occupying 3 L volume is expanded against a constant external pressure of 1 bar to a volume of 15 L . Calculate work done by the system

Which from the following defines enthalpy of a system?

Which of the following symbols represent heat of reaction at constant volume?

Calculate the entropy change for melting 1 g ice at $0^{\circ} \mathrm{C}$ in $\mathrm{Jg}^{-1} \mathrm{~K}^{-1}$ if heat of fusion of ice at $0^{\circ} \mathrm{C}$ is $80 \mathrm{~J} \mathrm{~K}^{-1}$.