In which case is the change in entropy negative?

Which of the following is a state function?

$30.4 \, kJ$ of heat is required to melt one mole of sodium chloride and the entropy change at the melting point is $28.4 \, J \, K^{-1} \, mol^{-1}$ at $1 \, atm$. The melting point of sodium chloride is $........... \, K$ (Nearest Integer).

Given $\Delta S_{Total} = -40 \ kJ/mol \cdot K$,$\Delta H_{System} = 2000 \ kJ/mol$,and $T = 400 \ K$. Find the value of $\Delta S_{System}$ in $kJ/mol \cdot K$.

Entropy is a measure of .......

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