How much energy is needed to turn 20 g water into steam if the water was at a temperature

How much energy is needed to turn 20 g water into steam if the water was at a temperature of 20 degrees Celsius? specific heat of vaporization of water 2.3 MJ / kg. specific heat of water 4200J / kg * degrees Celsius.

1) Before evaporating water, it must be brought to a boil so that the evaporation process is intense. To calculate how much heat the water should receive by heating to the boiling point = 100 degrees, we will use the formula: Q = m • c • Δt. Specific heat capacity of water c = 4200 J / (kg • deg), temperature change Δt = 100 – 20; Δt = 80 degrees, water mass m = 20 g = 0.02 kg. We substitute the values ​​of physical quantities: Q = 0.02 kg • 4200 J / (kg • deg) • 80 deg = 6720 J.
2) To calculate how much heat the boiling water must receive in order to evaporate, we use the formula Q = L • m, where the specific heat of vaporization of water is L = 2.3 MJ / kg. We substitute the values ​​of physical quantities: Q = 0.02 kg • 2300000 J / kg = 46000 J.
3) Let’s find how much energy is required for both processes. Q = 46000 J + 6720 J = 52720 J.
Answer: 52720 J of energy is needed to convert this water into steam.