How much energy is required to melt a piece of copper with a mass of 10 kg if the initial

How much energy is required to melt a piece of copper with a mass of 10 kg if the initial temperature of copper is 13 degrees Celsius.

The amount of energy required to melt copper:
Q = Q1 + Q2.
Q1 = C * m * (tк – tн), C – beats. heat capacity of copper (С = 385 J / (К * kg)), m – mass of a piece of copper (m = 10 kg), tк – melting temperature (tк = 1083 ºС), tн – initial temperature (tн = 13 ºС).
Q1 = C * m * (tc – tn) = 385 * 10 * (1083 – 13) = 385 * 10 * 1070 = 4119500 J ≈ 4.12 MJ.
Q2 = λ * m, λ – beats. heat of fusion of copper (λ = 2.1 * 10 ^ 5 J / kg).
Q2 = (2.1 * 10 ^ 5) * 10 = 2.1 * 10 ^ 6 = 2.1 MJ.
Q = Q1 + Q2 = 4.12 + 2.1 = 6.22 MJ.
Answer: It takes 6.22 MJ of energy to melt a piece of copper.