How many kilograms of water taken at a temperature of 20 ° C can be brought to a boil with heat in the amount of 25 kJ?

To calculate the mass of water brought to a boil, we will use the formula: Q = Cw * m * (tc – t), from where we express: m = Q / (Cw * (tc – t)).

Constants and variables: Q – the amount of transferred heat (Q = 25 kJ = 25 * 10 ^ 3 J); Sv – specific heat of water (Sv = 4200 J / (kg * ºС)); tк – temperature of the beginning of boiling (tк = 100 ºС); t – initial temperature (t = 20 ºС).

Calculation: m = 25 * 10 ^ 3 / (4200 * (100 – 20)) = 0.0744 kg.

Answer: It will be possible to bring 0.0744 kg of water to a boil.