How many grams of gunpowder do you need to burn to get 57kJ of heat?

Initial data: Q (the amount of heat obtained from the combustion of gunpowder) = 57 kJ (57 * 10 ^ 3 J).

Reference values: q (specific heat of combustion of gunpowder) = 0.38 * 10 ^ 7 J / kg.

The mass of burnt gunpowder can also be determined by the formulas: Q = q * m, whence m = Q / q.

Let’s calculate: m = 57 * 10 ^ 3 / (0.38 * 10 ^ 7) = 0.015 kg (15 g).

Answer: To obtain 57 kJ of heat, you need to burn 15 grams of gunpowder.