Using Hess's Law, calculate the heat of formation of propane given the following reactions: 1. C(s) + O2(g) -> CO2(g), ΔH = -393.5 kJ/mol 2. H2(g) + 1/2 O2(g) -> H2O(l), ΔH = -285.8 kJ/mol 3. C3H8(g)

You've provided the additional data needed to solve part (b) of question 7. Let's calculate the heat of formation of propane using Hess's Law.

The target reaction for the heat of formation of propane ($\text{C}_3\text{H}_8$) is:

$$3\text{C(s)} + 4\text{H}_2\text{(g)} \longrightarrow \text{C}_3\text{H}_8\text{(g)} \quad \Delta H_f^\circ (\text{C}_3\text{H}_8)$$

We have the following given reactions and their enthalpy changes:

1. $\text{C(s)} + \text