Question

In the following reaction, how much heat is generated when 1.55 moles of CH₄ are burned?
CH₄ (g) + 2 O₂ (g) → CO₂ (g) + 2 H₂O(g) ∆H° = -802 kJ/mol

Answer 1

$\begin{aligned} ΔH &= nΔH˚\\ ΔH &= 1.55mol\ CH_4 × \dfrac{-802kJ}{1mol\ CH_4\ in\ rxn}\\ ΔH &= −1243.1kJ \end{aligned}$

Note that the heat generated is negative because the reaction is exothermic and thus loses that amount of heat during combustion.