$A$ container has a hydrogen and oxygen mixture in a ratio of $4 : 1$ by weight. When these gases are mixed,which of the following occurs?

The entropy change,in the conversion of one mole of liquid water at $373 \, K$ to vapour at the same temperature is (Latent heat of vaporization of water,$\Delta H_{vap} = 2.257 \, kJ/g$) ........ $J \, K^{-1}$ (in $.9$)

Calculate the entropy change in $JK^{-1}$ for the reversible expansion of $5 \ mol$ of an ideal gas at $27 \ ^oC$ from $8 \ dm^3$ to $80 \ dm^3$.

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 $kJ/mol \cdot K$.

Standard entropies of $X_2, Y_2$ and $XY_5$ are $70, 50$ and $110 \ J \ K^{-1} \ mol^{-1}$ respectively. The temperature in Kelvin at which the reaction $\frac{1}{2} X_2 + \frac{5}{2} Y_2 \rightarrow XY_5$ with $\Delta H = -35 \ kJ \ mol^{-1}$ will be at equilibrium is . . . . . . (Nearest integer).

Find the change in entropy for the fusion of $1 \, mol$ of ice in $J \, K^{-1} \, mol^{-1}$. The melting point of water is $273 \, K$ and the molar enthalpy of fusion for water is $6.0 \, kJ \, mol^{-1}$.