How much heat is needed to heat 1 kg of water from 20 degrees C to boiling point?

Problem data: m (the mass of water that needs to be brought to a boil) = 1 kg; t0 (initial temperature) = 20 ºС.

Reference values: Cw (specific heat) = 4200 J / (kg * K); tboil (required temperature, boiling point) = 100 ºС.

The heat expended for heating 1 kg of water is determined by the formula: Q = Sv * m * (tboil – t0).

Let’s calculate: Q = 4200 * 1 * (100 – 20) = 336 * 10 ^ 3 J (336 kJ).

Answer: you need 336 kJ of heat.