With the complete combustion of dry wood, 50,000 kJ of energy was released. How much firewood was burnt?

Initial data: Q (the amount of heat released during the combustion of dry wood) = 50,000 kJ = 50 * 10 ^ 6 J.

Reference data: q (specific heat of combustion of dry wood) = 1 * 10 ^ 7 J / kg.

We calculate the mass of burnt dry firewood from the formula: Q = q * m, whence m = Q / q.

Let’s calculate: m = 50 * 10 ^ 6 / (1 * 10 ^ 7) = 5 kg.

Answer: Dry firewood weighing 5 kilograms was burnt.