**Part A) Calculate the enthalpy change, ΔH, for the expansion of methane:**

We can use the following equation to solve for **ΔH˚ _{rxn}**:

$\overline{){\mathbf{\Delta H}}{{\mathbf{\xb0}}}_{{\mathbf{rxn}}}{\mathbf{=}}{\mathbf{\Delta H}}{{\mathbf{\xb0}}}_{\mathbf{f}\mathbf{,}\mathbf{}\mathbf{prod}}{\mathbf{-}}{\mathbf{\Delta H}}{{\mathbf{\xb0}}}_{\mathbf{f}\mathbf{,}\mathbf{}\mathbf{react}}}$

Note that we need to *multiply each ΔH˚ _{f} by the stoichiometric coefficient* since ΔH˚

Also, note that ΔH˚_{f} for elements in their standard state is 0.

**CH _{4}(g) → C(g) + 4 H(g)**

Part A

Calculate the enthalpy change, ΔH, for the expansion of methane

CH_{4}(g) → C(g) + 4H(g)

Part B

Calculate the enthalpy change, ΔH for the reverse of the formation of methane.

CH_{4}(g) → C(s) + 2 H_{2}(g)

Part C

Suppose that 0.570 mol of methane CH_{4}(g) is reacted with 0.720 mol of fluorine, F_{2}(g), forming CF_{4}(g) and HF (g) as sole products. Assuming that the reaction occurs at constant pressure, how much heat is released?

Frequently Asked Questions

What scientific concept do you need to know in order to solve this problem?

Our tutors have indicated that to solve this problem you will need to apply the Enthalpy of Formation concept. You can view video lessons to learn Enthalpy of Formation. Or if you need more Enthalpy of Formation practice, you can also practice Enthalpy of Formation practice problems.