The heat of combustion of solid benzoic acid at constant volume is $-321.30 \ kJ$ at $27^{\circ} C$. The heat of combustion at constant pressure is $(-321.30 - x R) \ kJ$. The value of $x$ is . . . . . . .

The enthalpies of formation of $CO_{2(g)}$ and $CaO_{(s)}$ are $-94.0 \, kJ$ and $-152 \, kJ$ respectively. The enthalpy of the reaction $CaCO_{3(s)} \rightarrow CaO_{(s)} + CO_{2(g)}$ is $42 \, kJ$. The enthalpy of formation of $CaCO_{3(s)}$ is ............... $kJ$.

For the reaction $R \rightarrow P$,the following potential energy diagram is given. What will be the enthalpy change $(\Delta H)$ for the given reaction (in $kJ$)?

The energy absorbed by each molecule $(A_2)$ of a substance is $4.4 \times 10^{-19} \ J$ and bond energy per molecule is $4.0 \times 10^{-19} \ J.$ The kinetic energy of the molecule per atom will be $...... \times 10^{-20} \ J$

The heat of hydrogenation of cyclohexene is $28.6 \, kcal$ and that of cyclohexadiene is slightly more than double,$(55.4 \, kcal)$. What will be the heat of hydrogenation of benzene,which contains three double bonds?

Hess's law deals with