Lead with a mass of m = 0.1 kg taken at 20 ° C is heated to the melting point and melted.
| January 24, 2021 | education
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.
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