For a spontaneous process,

If $900 \ J/g$ of heat is exchanged at the boiling point of water,what is the increase in entropy in $J \ K^{-1} \ mol^{-1}$?

In which of the following reactions,standard reaction entropy change $(\Delta S^o)$ is positive and standard Gibb's energy change $(\Delta G^o)$ decreases sharply with increasing temperature?

One mole of ice is converted into water at $1 \ atm$ and $273 \ K$. The entropies of $H_2O_{(s)}$ and $H_2O_{(\ell)}$ are $38.2$ and $60.01 \ J \ mol^{-1} \ K^{-1}$ respectively. The enthalpy change for the conversion is ...... $J \ mol^{-1}$.

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

For a $Carnot$ engine,the source is at $500 \ K$ and the sink at $300 \ K$. What is the efficiency of this engine?