For an isolated system,$\Delta U = 0,$ what will be $\Delta S?$

For a sample of a perfect gas,when its pressure is changed isothermally from $p_i$ to $p_f$,the entropy change is given by:

The value of entropy of the universe is

The entropy change for the conversion of $1 \, \text{mol}$ of liquid water to steam at $373 \, K$ is ...... $J/K$ (Given: $\Delta H_{\text{vap}} = 2.257 \, kJ/g$). (in $0.9$)

In which of the following reactions is $\Delta S$ positive?

At $1 \ atm$ pressure,if $\Delta S_{\text{vap}} = 75 \ J \ K^{-1} \ mol^{-1}$ and $\Delta H_{\text{vap}} = 30 \ kJ \ mol^{-1}$,what will be the boiling point of the liquid in $K$?