# Lead with a mass of m = 0.1 kg taken at 20 ° C is heated to the melting point and melted.

Lead with a mass of m = 0.1 kg taken at 20 ° C is heated to the melting point and melted. Find the total change in the internal energy if the specific heat of fusion of lead λ = 22.6 kJ / kg, …

Given: m (mass of taken lead) = 0.1 kg; t0 (initial temperature) = 20 ºС.

Constants: Сс (specific heat capacity of lead) = 140 J / (kg * K); tmelt (temperature of the beginning of melting) = 327.4 ºС; according to the condition λ (specific heat of fusion) = 22.6 kJ / kg = 22.6 * 10 ^ 3 J / kg.

The required total change in the internal energy of the taken lead: Q = Сс * m * (tpl – t) + λ * m.

Calculation: Q = 140 * 0.1 * (327.4 – 20) + 22.6 * 10 ^ 3 * 0.1 = 6563.6 J.

Answer: The internal energy of the taken lead will increase by 6563.6 J.

One of the components of a person's success in our time is receiving modern high-quality education, mastering the knowledge, skills and abilities necessary for life in society. A person today needs to study almost all his life, mastering everything new and new, acquiring the necessary professional qualities.