Ice was heated on a wood-burning stove from -20 degrees to 0 degrees.

Ice was heated on a wood-burning stove from -20 degrees to 0 degrees. Determine the amount of firewood burnt if there was ice in a 5 liter pot.

Q1 = Q2.

Q1 (heating of ice, heating of a pan is not taken into account, transformation into water is not specified) = C * m1 * (tк – tн); C – beats. heat capacity (C = 2100 J / (K * kg)), m – ice mass (m = ρ * V; ρ – density (ρ = 900 kg / m3), V – pot volume (V = 5 l = 0.005 m3) ), tк = 0 ºС, tн = -20 ºС.

Q2 (wood burning) = q * m2; q – beats. heat of combustion (q = 1 * 10 ^ 7 J / kg), m2 is the desired mass.

C * ρ * V * (tк – tн) = q * m2.

m2 = (C * ρ * V * (tc – tn)) / q = 2100 * 900 * 0.005 * (0 – (-20)) / 10 ^ 7 = 0.0189 kg = 18.9 g.