m = 200 g = 0.2 kg.
λ = 0.9 * 10 ^ 6 J / kg.
t = 78 ° C.
When a substance condenses at the boiling point, the amount of heat Q that is released is determined by the formula: Q = λ * m, where λ is the specific heat of vaporization of the substance, m is the mass of the substance that condenses.
Alcohol is at a boiling point of t = 78 ° C.
Q = 0.9 * 10 ^ 6 J / kg * 0.2 kg = 180 * 10 ^ 3 J ..
Answer: during crystallization of the lead plate, Q = 18250 J of thermal energy will be released.
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