How much heat must be spent to melt an iron part weighing 2 kg, if its initial temperature is 39 degrees?

Given: m (mass of an iron part for melting) = 2 kg; t (part temperature before heating) = 39 ºС.

Reference values: С (specific heat of iron) = 460 J / (kg * ºС); tmelt (temperature of the beginning of melting of the part) = 1539 ºС; λ (specific heat of fusion of iron) = 27 * 10 ^ 4 J / kg.

1) Heating of the iron part: Q1 = C * m * (tm – t) = 460 * 2 * (1539 – 39) = 138 * 10 ^ 4 J.

2) Melting of the iron part: Q2 = λ * m = 27 * 10 ^ 4 * 2 = 54 * 10 ^ 4 J.

3) Heat: Q = Q1 + Q2 = 138 * 10 ^ 4 + 54 * 10 ^ 4 = 192 * 10 ^ 4 J.