Given: $C + O_2 \rightarrow CO_2$ : $\Delta H = -395 \ kJ$,$S + O_2 \rightarrow SO_2$ : $\Delta H = -295 \ kJ$,$CS_2 + 3O_2 \rightarrow CO_2 + 2SO_2$ : $\Delta H = -1110 \ kJ$. Calculate the heat of formation of $CS_2$ in $kJ/mol$.

If bond enthalpies of $N \equiv N$,$H - H$ and $N - H$ bonds are $x_1, x_2$ and $x_3$ respectively,$\Delta H_f^o$ for $NH_3$ will be

The enthalpy change during a reaction does not depend on .......

For the reaction $2H_2O_2(\ell) \to 2H_2O(\ell) + O_2(g)$,what is the enthalpy change? Given that the heats of formation of $H_2O_2(\ell)$ and $H_2O(\ell)$ are $-188 \, kJ/mol$ and $-286 \, kJ/mol$ respectively.

Calculate the heat of combustion (in $kJ$) of methane from the following data:
$(i)$ $C_{\text{(graphite)}} + 2H_{2(g)} \rightarrow CH_{4(g)} \quad \Delta H = -74.8 \ kJ$
(ii) $C_{\text{(graphite)}} + O_{2(g)} \rightarrow CO_{2(g)} \quad \Delta H = -393.5 \ kJ$
(iii) $H_{2(g)} + 1/2 O_{2(g)} \rightarrow H_2O_{(l)} \quad \Delta H = -286.2 \ kJ$

On combustion,carbon forms two oxides $CO$ and $CO_2$. The heat of formation of $CO_2$ gas is $-94.3 \, kcal$ and that of $CO$ is $-26.0 \, kcal$. The heat of combustion of carbon is.......$kcal$.