# Combustion of Propane: Calculating Heat Release

## What is the heat associated with the complete combustion of propane?

How can we calculate the heat released when all of the propane in the tank undergoes complete combustion?

## Calculating Heat Release from Propane Combustion

When propane, C3H8, undergoes complete combustion, the heat released can be calculated using the enthalpy of combustion. To determine the heat associated with the complete combustion of propane, we need to convert the mass of propane to moles, utilize the balanced chemical equation for combustion, and apply the enthalpy of combustion for CO2.

The enthalpy change for the combustion of propane can be determined by considering the balanced chemical equation:

**C3H8 + 5O2 -> 3CO2 + 4H2O**

From this equation, we observe that each mole of propane produces 3 moles of CO2 and 4 moles of water vapor. By leveraging the molar mass of propane, we can convert the mass of propane to moles and subsequently calculate the moles of CO2 produced during combustion. The enthalpy of combustion for CO2 (-393.5 kJ/mol) can then be used to determine the heat released.

To calculate the heat associated with the complete combustion of propane, we follow these steps:

- Convert the mass of propane to moles:
- Convert the moles of propane to moles of CO2:
- Calculate the heat released:

Moles of C3H8 = 13.2 kg / 44.1 g/mol = 299.1 mol

Moles of CO2 = 299.1 mol C3H8 x (3 mol CO2 / 1 mol C3H8) = 897.3 mol CO2

Heat released = moles of CO2 x enthalpy of combustion of CO2

Heat released = 897.3 mol x (-393.5 kJ/mol)

Therefore, the heat associated with the complete combustion of all of the propane in the tank is -352,774.55 kJ, or approximately -353 kJ.