$6 \ g$ of graphite is burnt in a bomb calorimeter at $25^{\circ} C$ and $1 \ atm$ pressure. The temperature of water increased from $25^{\circ} C$ to $31^{\circ} C$. If $\Delta H$ of this reaction is $-248 \ kJ \ mol^{-1}$,find out $C_V$ (in $kJ \ K^{-1}$) of the bomb calorimeter.

Products are favoured in a chemical reaction taking place at a constant temperature and pressure. Consider the following statements: $(i)$ The change in Gibbs energy for the reaction is negative. $(ii)$ The total change in Gibbs energy for the reaction and the surroundings is negative. $(iii)$ The change in entropy for the reaction is positive. $(iv)$ The total change in entropy for the reaction and the surroundings is positive. The statements which are always true are:

$2.2 \, g$ of nitrous oxide $(N_{2}O)$ gas is cooled at a constant pressure of $1 \, atm$ from $310 \, K$ to $270 \, K$ causing the compression of the gas from $217.1 \, mL$ to $167.75 \, mL$. The change in internal energy of the process,$\Delta U$ is $-x \, J$. The value of $x$ is $....$ [nearest integer] (Given: atomic mass of $N = 14 \, g \, mol^{-1}$ and of $O = 16 \, g \, mol^{-1}$. Molar heat capacity of $N_{2}O$ is $100 \, J \, K^{-1} \, mol^{-1}$)

Find the enthalpy of neutralisation in $kJ/mol$ for the reaction between $NH_4OH$ and $HCN$ in aqueous solution,given that the enthalpies of ionisation of $NH_4OH$ and $HCN$ are $7 \ kJ/mol$ and $8 \ kJ/mol$ respectively,and the enthalpy of neutralisation of a strong acid and a strong base is $-57.3 \ kJ/mol$.

Calculate the work done during the combustion of $0.138 \ kg$ of ethanol,$(C_2H_5OH_{(l)})$ at $300 \ K$. Given: $R = 8.314 \ J \ K^{-1} \ mol^{-1}$ and molar mass of ethanol $= 46 \ g \ mol^{-1}$. (in $J$)

Enthalpy of hydrogenation of one mole of benzene to cyclohexane is
$[$Resonance energy of benzene $= -150.4 \ kJ / mol$.
Enthalpy of hydrogenation of cyclohexene $= -119.5 \ kJ / mol$ $]$