What is the unit of $\Delta S_m^\circ$?

The entropy of a sample of a certain substance increases by $0.836 \ J \ K^{-1}$ on adding reversibly $0.3344 \ J$ of heat at constant temperature. The temperature of the sample is.....$K$

One mole of an ideal gas is expanded isothermally and reversibly to half of its initial pressure. $\Delta S$ for the process in $J \ K^{-1} \ mol^{-1}$ is $[\ln \ 2 = 0.693$ and $R = 8.314 \ J \ mol^{-1} \ K^{-1}]$

Which of the following statements is incorrect?

What is entropy?

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