When a solid melts reversibly,which of the following occurs?

What is the entropy of vaporisation of water at $100\,^{\circ}C$,if the molar heat of vaporisation is $9710\,cal/mol$?

The enthalpy change for the transition of liquid water to steam at $373 \, K$ is $40.8 \, kJ \, mol^{-1}$. What is the $\Delta S$ for the process in $J \, K^{-1} \, mol^{-1}$?

For which of the following processes,$\Delta S$ is negative?

Given $\Delta _rS^o = -266 \ J \ K^{-1}$ and the listed $S_m^o$ values,calculate $S^o$ for $Fe_3O_{4(s)}$ for the reaction: $4 Fe_3O_{4(s)} + O_{2(g)} \to 6 Fe_2O_{3(s)}$. Given $S_m^o(Fe_2O_3) = 87 \ J \ K^{-1} \ mol^{-1}$ and $S_m^o(O_2) = 205 \ J \ K^{-1} \ mol^{-1}$.

Which state functions are required to understand the second law of thermodynamics?