How much energy is needed to melt 18kg of lead taken at a temperature of 17 degrees Celsius.

univerkov | August 2, 2021 | education

To calculate the heat energy expended for smelting 18 kg of lead, we apply the formula: Q = Cc * m * (tp – t) + λ * m = m * (Cc * (tp – t) + λ).

Constants and variables: m is the mass of taken lead (m = 18 kg); Cc – heat capacity of lead (Cc = 140 J / (kg * K)); tp – melting point (tp = 327.4 ºС ≈ 327 ºС); t – initial temperature (t = 17 ºС); λ is the heat of fusion of lead (λ = 0.25 * 10 ^ 5 J / kg).

Calculation: Q = m * (Cc * (tmelt – t) + λ) = 18 * (140 * (327 – 17) + 0.25 * 10 ^ 5) = 1231200 J ≈ 1.23 MJ.

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.