How much heat is required to melt 150g of silver taken at a temperature of 20 degrees?

Data: m (mass of silver to be melted) = 150 g (0.15 kg); t (temperature of silver before heating) = 20 ºС.

Constants: С (specific heat capacity) = 250 J / (kg * ºС); tmelt (temperature of the beginning of silver melting) = 961.9 ºС; λ (specific heat of fusion) = 87 * 10 ^ 3 J / kg.

1) Heating to a temperature of 961.9 ºС: Q1 = C * m * (tmelt – t) = 250 * 0.15 * (961.9 – 20) = 35321.25 J.

2) Melting: Q2 = λ * m = 87 * 10 ^ 3 * 0.15 = 13050 J.

3) Q = Q1 + Q2 = 35321.25 + 13050 = 48371.25 J (≈ 48.4 kJ).