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

From the given diagram, the enthalpy change $\Delta_r H$ for the reaction $C \rightarrow A$ is:

State Hess's Law of Constant Heat Summation.

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) $H_{2(g)} + 1/2 O_{2(g)} \rightarrow H_2O_{(l)} \quad \Delta H = -286.2 \ kJ$

When $2 \, mol$ of $C_2H_6$ is completely combusted,$3129 \, kJ$ of heat is released. The heat of formation of $C_2H_6$ is ..... $kJ/mol$. Given that $\Delta H_f$ for $CO_2$ and $H_2O$ are $-395 \, kJ/mol$ and $-286 \, kJ/mol$ respectively.

The standard heats of formation for $CH_4$, $C_2H_4$, and $C_3H_8$ are $-17.9$, $12.5$, and $-24.8 \ kcal/mol$ respectively. The heat of reaction $(\Delta H)$ for the reaction $CH_4 + C_2H_4 \rightarrow C_3H_8$ in $kcal$ is: