Many portable gas heaters and grills use propane, C3H8(g). Using enthalpies of formation, calculate the quantity of heat produced when 13.0 g of propane is completely combusted in air under standard conditions. Assume that liquid water is forming. Express the heat in kilojoules to three significant digits.

The amount of heat released is -603. kJ

Explanation:

Enthalpy change is defined as the difference in enthalpies of all the product and the reactants each multiplied with their respective number of moles.

The equation used to calculate enthalpy change is of a reaction is:

The chemical equation for the combustion of propane follows:

The equation for the enthalpy change of the above reaction is:

We are given:

Putting values in above equation, we get:

To calculate the number of moles, we use the equation:

Given mass of propane = 13.0 g

Molar mass of propane = 44 g/mol

Putting values in above equation, we get:

To calculate the enthalpy change of the reaction, we use the equation:

where,

q = amount of heat released = ?

n = number of moles of propane = 0.295 moles

= enthalpy change of the reaction  = -2044.01 kJ/mol

Putting values in above equation, we get:

Hence, the amount of heat released is -603. kJ

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