To evaporate 500 grams of water, it took the same amount as when burning

To evaporate 500 grams of water, it took the same amount as when burning 2 kg of wood. Determine the specific heat of combustion of firewood.

Initial data: m1 (mass of evaporated water) = 500 g = 0.5 kg; m2 (mass of burnt wood) = 2 kg.

Reference data: L (specific heat of vaporization of water) = 2.3 MJ / kg = 2.3 * 10 ^ 6 J / kg.

The specific heat of combustion of firewood is determined from the following equality: L * m1 = q * m2, whence q = L * m1 / m2.

Let’s calculate: q = 2.3 * 10 ^ 6 * 0.5 / 2 = 0.575 * 10 ^ 6 J / kg = 575 kJ / kg.

Answer: According to the calculation, the specific heat of combustion of firewood is 575 kJ / kg.