The Enthalpy of Combustion of Butane
Introduction
Butane (C4H10) combusts in the presence of oxygen to form carbon dioxide (CO2) and water (H2O). The enthalpy of combustion for butane can be calculated using the given heat of formation values.
Calculating Enthalpy of Combustion
Given:
Heat of formation of C4H10 = -125.7 kJ/mol
Heat of formation of water = -241.82 kJ/mol
Heat of formation of CO2 = -393.5 kJ/mol
Using the formula:
ΔH = ∑Hproducts - ∑Hreactants
ΔH = 8(-393.5) + 10(-241.82) - 2(-125.7)
ΔH = -5314.8 kJ/mol
This energy would result in the combustion of 2 moles of butane. Therefore, energy required for the combustion of 1 mole of butane is:
-2657.4 kJ/mol
How is the enthalpy of combustion of butane calculated?
The enthalpy of combustion of butane is calculated by subtracting the sum of the heat of formation of reactants from the sum of the heat of formation of products. In this case, the enthalpy of combustion value is -2657.4 kJ/mol.