How much heat is needed to melt 100 g of naphthalene, taken at a temperature of 20 degrees.
| March 2, 2021 | education
Given: m (mass of naphthalene taken) = 100 g (in SI m = 0.1 kg); t0 (initial temperature of naphthalene) = 20 ºС.
Constant values: Cн (specific heat capacity of naphthalene) = 1300 J / (kg * K); λ (beats heat of fusion) = 151 kJ / kg = 151 * 10 ^ 3 J / kg; tmelt (melting point) = 80.26 ºС ≈ 80 ºС.
The required heat for melting 100 g of naphthalene: Q = Q1 + Q2 = Cн * m * (tmelt – t0) + λ * m.
Calculation: Q = 1300 * 0.1 * (80 – 20) + 151 * 10 ^ 3 * 0.1 = 22900 J = 22.9 kJ.
Answer: You need 22.9 kJ of heat.
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