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

Enthalpy of vaporization of benzene is $+35.3 \ kJ \ mol^{-1}$ at its boiling point,$80^{\circ} C$. The entropy change in the transition of the vapour to liquid at its boiling point in $[J \ K^{-1} \ mol^{-1}]$ is

Which of the following has the highest entropy?

When two gases are mixed,the entropy $......$

Give the mathematical equation for entropy change.

Will ice at $273 \ K$ placed in a surrounding at $298 \ K$ melt to form water at $273 \ K$? Prove this statement. The molar enthalpy of fusion of ice is $6.025 \ kJ \ mol^{-1}$.