Question

Define Enthalpy of Combustion.

Answer 1

• Combustion reaction is the process in which reactants undergo reaction with the Oxygen molecule $\left({\mathrm{O}}_2\right)$ to form the desired product along with the evolution of heat. In the case of hydrocarbons, Carbon dioxide $\left({\mathrm{CO}}_2\right)$ and Water $\left({\mathrm{H}}_2\mathrm{O}\right)$ are generated as products in the combustion reaction.
• $\mathrm{Hydrocarbon}+{\mathrm{O}}_2\to {\mathrm{CO}}_2+{\mathrm{H}}_2\mathrm{O}$
• Heat consumed or evolved at constant pressure is termed enthalpy change $\left(∆\mathrm{H}\right)$. Enthalpy change associated with the combustion of any substance is known as its enthalpy of combustion and it is denoted by $∆{\mathrm{H}}_{\mathrm{c}}$.