Expansion of $1$ $mol$ of an ideal gas takes place from $2$ $L$ to $8$ $L$ at $300$ $K$ against a constant external pressure of $1$ $atm$. Calculate $\Delta S_{total}$ in $J$ $K^{-1}$ $mol^{-1}$.
(Given: $R = 8.3$ $J$ $K^{-1}$ $mol^{-1}$,$1$ $L$ $atm = 100$ $J$,$\ln 2 = 0.693$) (in $.5$)

$A$ fish swimming in a water body,when taken out,is covered with a film of water of weight $36 \ g$. When it is subjected to cooking at $100^{\circ} C$,the internal energy change for vaporization in $kJ \ mol^{-1}$ is $......$ [nearest integer].
[Assume steam to be an ideal gas. Given $\Delta_{vap} H^{\ominus}$ for water at $373 \ K$ and $1 \ bar$ is $41.1 \ kJ \ mol^{-1}$; $R = 8.31 \ J \ K^{-1} \ mol^{-1}$]

$A$ $10 \ g$ piece of iron $(C = 0.45 \ J/g \ ^oC)$ at $100 \ ^oC$ is dropped into $25 \ g$ of water $(C = 4.2 \ J/g \ ^oC)$ at $27 \ ^oC$. Find the temperature of the iron and water system at thermal equilibrium in $^oC$.

For the reaction: $A_{(g)} + B_{(s)} \rightleftharpoons 2C_{(g)} + D_{(g)}$,given $\Delta U = 5.0 \ kcal$ and $\Delta S = 50 \ cal \ K^{-1}$ at $400 \ K$. Calculate $\Delta G$ for the reaction. (in $kcal$)

Enthalpy of combustion of $CH_4, C_2H_6$ and $C_3H_8$ are $-210.8, -368.4$ and $-526.2 \ k \ cal \ mol^{-1}$ respectively. Enthalpy of combustion of hexane can be predicted as........$k \ cal \ mol^{-1}$

$A$ gas expands from $3 \ dm^{3}$ to $5 \ dm^{3}$ against a constant pressure of $3 \ atm$. The work done during this expansion is used to heat $10 \ mol$ of water at $290 \ K$. What will be the final temperature of the water in $K$? (Specific heat of water = $4.184 \ J \ g^{-1} \ K^{-1}$)