Determine the mass of coal if 4.5 * 10 ^ 8 J of heat is released during its combustion.

Given:

Q = 4.5 * 10 ^ 8 Joules – the amount of heat released during the combustion of coal;

q = 30 * 10 ^ 6 Joule / kilogram – specific heat of combustion of coal (specific heat of combustion of coal depends on its type, in this case the maximum value is taken).

It is required to determine m (kilogram) – what mass of coal was burnt.

Since the problem statement is not specified, we assume that the combustion was complete. Then, to determine the mass, you must use the following formula:

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

m = Q / q = 4.5 * 10 ^ 8 / (30 * 10 ^ 6) = 450/30 = 15 kilograms.

Answer: the mass of burnt coal is 15 kilograms.