How much energy needs to be spent to bring water with a mass of 5 kg, taken at a temperature of 0 C
| September 8, 2021 | education
How much energy needs to be spent to bring water with a mass of 5 kg, taken at a temperature of 0 C, to a boil and evaporate it?
Q = Q1 + Q2.
Q1 = C * m * (tк – tн), where C is the specific heat capacity of water (C = 4200 J / (K * kg)), m is the mass of water (m = 5 kg), tк is the final water temperature (tк = 100 ºС), tн – initial water temperature (tн = 0 ºС).
Q2 = L * m, where L is the specific heat of vaporization of water (L = 2.3 * 106 J / kg).
Q = Q1 + Q2 = C * m * (tc – tn) + L * m = 4200 * 5 * (100 – 0) + 2.3 * 106 * 5 = 2100000 + 11500000 = 13600000 J = 13.6 MJ.
Answer: It is necessary to spend 13.6 MJ of thermal energy.
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