Heat of combustion of $CH_4, C_2H_4$ and $C_2H_6$ are $-890, -1411$ and $-1560 \ kJ/mol$ respectively. Which has the lowest calorific value?

The enthalpies of combustion of cyclohexane $(C_6H_{12})$, cyclohexene $(C_6H_{10})$ and $H_2$ are $-3920 \text{ kJ mol}^{-1}$, $-3800 \text{ kJ mol}^{-1}$ and $-241 \text{ kJ mol}^{-1}$ respectively. The enthalpy of hydrogenation of cyclohexene is

The heat of combustion of carbon to $CO_2$ is $-393.5 \text{ kJ/mol}$. The heat released upon formation of $35.2 \text{ g}$ of $CO_2$ from carbon and oxygen gas is

$CsOH + HCl \to CsCl + H_2O$,$\Delta H = -13.4 \ K \ cal/mol$
$CsOH + HA \to CsA + H_2O$,$\Delta H = -10.4 \ K \ cal/mol$
Then calculate $\Delta H$ of ionisation of $HA$ in $K \ cal/mol$.

Calculate the work done for the following reaction at $27^{\circ}C$: $C_2H_4(g) + H_2(g) \rightarrow C_2H_6(g)$ $(R = 8.314 \text{ J K}^{-1} \text{mol}^{-1})$ (in $\text{ J}$)

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 $.5$)