How much heat is needed to vaporize 400 grams of mercury if the initial temperature is 57 degrees Celsius?

univerkov | March 28, 2021 | education

Initial data: m (mass of mercury taken) = 400 g (0.4 kg); t0 (temperature of mercury before heating) = 57 ºС.

Reference values: C (specific heat of mercury) = 140 J / (kg * K); tpap (temperature of the beginning of vaporization of mercury) = 357 ºС; L (specific heat of vaporization of mercury) = 0.3 * 10 ^ 6 J / kg.

The required amount of heat is determined by the formula: Q = C * m * (tp – t0) + L * m = (C * (tp – t0) + L) * m.

Calculation: Q = (140 * (357 – 57) + 0.3 * 10 ^ 6) * 0.4 = 136 800 J (136.8 kJ).

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