What mass of kerosene needs to be burned in order to release 86 MJ of heat?

Q = 86 MJ (megajoules) – the required amount of heat;

q = 40.8 MJ / kg = 40.8 * 10 ^ 6 Joule / kilogram is the specific heat of combustion of kerosene.

It is required to determine m (kilogram) – how much kerosene must be burned in order to obtain heat equal to Q.

Let’s translate the units of energy measurement into the SI system:

Q = 86 MJ = 86 * 10 ^ 6 Joules.

Since the condition of the problem is not specified, we consider that the combustion of kerosene is complete. Then, to determine the mass, you must use the following formula:

Q = q * m, from here we find that:

m = Q / q = 86 * 10 ^ 6 / (40.8 * 10 ^ 6) = 86 / 40.8 = 860/408 = 2.1 kilograms (the result has been rounded to one decimal place).

Answer: you need to burn kerosene weighing 2.1 kilograms.