How much heat will be released during the complete combustion of a mixture of 2.5 kg of gasoline and 0.5 alcohol?

The amount of heat received from fuel combustion is determined by the formula:

Q = q * m, where Q is the amount of heat obtained during the combustion of fuel, q is the specific heat of combustion, in our case, gasoline (q = 4.6 * 10⁷ J / kg) and alcohol (q = 2.7 * 10⁷ J / kg), m is the mass of fuel (in our case, the mass of gasoline is 2.5 kg, the mass of alcohol is 0.5 kg).

The total amount of heat that will be released during the complete combustion of the mixture is

Q combustion of gasoline + Q combustion of alcohol –

4.6 * 10⁷ J / kg * 2.5 kg + 2.7 * 10⁷ J / kg * 0.5 kg = 11.5 * 10⁷ J + 1.35 * 10⁷ J.

Answer: when the fuel mixture is burned, according to the conditions of our example, an amount of heat will be released equal to 12.85 * 10⁷ J.