How much energy is spent on heating water weighing 0.75 kg from 20 to 100C and the subsequent formation of steam weighing 250 g?
January 17, 2021 | education
| To determine the cost of thermal energy for heating and vaporization of the taken water, we will use the formula: Q = L * m2 + Sv * m1 * (tp – t0).
Constants and variables: L – specific heat of vaporization (L = 2.3 * 10 ^ 6 J / kg); m2 – steam mass (m2 = 250 g = 0.25 kg); Sv – specific heat (Sv = 4200 J / (kg * ºС)); m1 is the total mass of water (m1 = 0.75 kg); tpar – temperature of vaporization (tpap = 100 ºС); t0 – initial temperature (t0 = 20 ºС).
Calculation: Q = L * m2 + Sv * m1 * (tpar – t0) = 2.3 * 10 ^ 66 * 0.25 + 4200 * 0.75 * (100 – 20) = 827 * 10 ^ 3 J = 827 kJ.
Answer: 827 kJ of thermal energy was spent.
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