Lead with a volume of 10 cm3, taken at an initial temperature of 20 degrees Celsius

Lead with a volume of 10 cm3, taken at an initial temperature of 20 degrees Celsius, will completely melt. how much heat was expended in this case?

The formula for calculating heat costs: Q = Q1 + Q2 = Cc * m * (tpl – t0) + λ * m = (Cc * (tpl – t0) + λ) * m = Cc * (tpl – t0) + λ) * ρc * V.

Variables and constants: Cc – heat capacity of lead (Cc = 140 J / (kg * K)); tm – temp. melting (melting point = 327.4 ºС); t0 – out. pace. (t0 = 20 ºС); λ is the heat of fusion of lead (λ = 0.25 * 10 ^ 5 J / kg); ρc – density (ρc = 11300 kg / m3); V – volume (V = 10 cm3 = 10 * 10-6 m3).

Calculation: Q = (140 * (327.4 – 20) + 0.25 * 10 ^ 5) * 11300 * 10 * 10 ^ -6 = 7688.068 J ≈ 7.7 kJ.