How much firewood needs to be burned to heat a 5 kg cast-iron pot. 10 degrees Celsius?

These tasks: m1 (mass of the heated cast-iron pot) = 5 kg; Δt (required change in pot temperature) = 10 ºС.

Reference values: Сч (specific heat capacity of cast iron) = 540 J / (kg * K); q (specific heat of combustion of dry wood) = 1 * 10 ^ 7 J / kg.

We express the mass of consumed dry firewood from the equality: q * m2 = Сч * m1 * Δt, whence m2 = Сч * m1 * Δt / q.

Let’s calculate: m2 = 540 * 5 * 10 / (1 * 10 ^ 7) = 0.0027 kg = 2.7 g.

Answer: To heat a cast-iron pot, you need to burn 2.7 g of dry wood.