Question: The Hf of $\mathrm{CO} 2(\mathrm{~g})$ is $-393.5 \mathrm{~kJ} / \mathrm{mol}$. The enthalpy of combustion of methane is $890.4 \mathrm{~kJ} / \mathrm{mole}$. Calculate the enthalpy of formation of methane.

The Hf of $\mathrm{CO} 2(\mathrm{~g})$ is $-393.5 \mathrm{~kJ} / \mathrm{mol}$. The enthalpy of combustion of methane is $890.4 \mathrm{~kJ}$ /mole. Calculate the enthalpy of formation of methane.

Question

Question: The Hf of $\mathrm{CO} 2(\mathrm{~g})$ is $-393.5 \mathrm{~kJ} / \mathrm{mol}$. The enthalpy of combustion of methane is $890.4 \mathrm{~kJ} / \mathrm{mole}$. Calculate the enthalpy of formation of methane.

The Hf of $\mathrm{CO} 2(\mathrm{~g})$ is $-393.5 \mathrm{~kJ} / \mathrm{mol}$. The enthalpy of combustion of methane is $890.4 \mathrm{~kJ}$ /mole. Calculate the enthalpy of formation of methane.

Accepted Answer

∻Solution∻ ‖ 1 ⋮ **Identify the given data**: The enthalpy of formation of $CO_2(g)$ is $-393.5 \, \text{kJ/mol}$ and the enthalpy of combustion of methane is $-890.4 \, \text{kJ/mol}$. ‖ ‖ 2 ⋮ **Write the balanced chemical equation for the combustion of methane**: $$ CH_4(g) + 2O_2(g) \rightarrow CO_2(g) + 2H_2O(l) $$ ‖ ‖ 3 ⋮ **Use the enthalpy of formation values**: The enthalpy change for the reaction can be calculated using the enthalpies of formation of the products and reactants. The enthalpy of formation of $H_2O(l)$ is $-285.8 \, \text{kJ/mol}$. ‖ ‖ 4 ⋮ **Apply Hess's Law**: $$ \Delta H_{\text{combustion}} = \Delta H_f (CO_2) + 2 \Delta H_f (H_2O) - \Delta H_f (CH_4) $$ Substitute the known values: $$ -890.4 \, \text{kJ/mol} = (-393.5 \, \text{kJ/mol}) + 2(-285.8 \, \text{kJ/mol}) - \Delta H_f (CH_4) $$ ‖ ‖ 5 ⋮ **Solve for the enthalpy of formation of methane**: $$ -890.4 = -393.5 - 571.6 - \Delta H_f (CH_4) $$ $$ -890.4 = -965.1 - \Delta H_f (CH_4) $$ $$ \Delta H_f (CH_4) = -965.1 + 890.4 $$ $$ \Delta H_f (CH_4) = -74.7 \, \text{kJ/mol} $$ ‖ ∻Answer∻ ⚹ The enthalpy of formation of methane is $-74.7 \, \text{kJ/mol}$. ⚹ ∻Key Concept∻ ⚹ Enthalpy of formation is the change in enthalpy when one mole of a compound is formed from its elements in their standard states. ⚹ ∻Explanation∻ ⚹ By using Hess's Law and the given enthalpy values, we can determine the enthalpy of formation of methane by rearranging and solving the equation for the enthalpy of formation. ⚹◊What is the enthalpy change for the combustion of methane?⍭ Generate me a similar question◊

Sia