What mass of water can be heated from 20 C ° to boiling, transferring 672 kJ of heat to the liquid?

Given:

T1 = 20 degrees Celsius – initial water temperature;

T2 = 100 degrees Celsius – boiling point of water;

Q = 672 kJ = 672 * 10 ^ 3 Joules – the amount of heat transferred to water;

c = 4200 J / (kg * C) – specific heat of water.

It is required to determine the mass of water m (kilogram) that can be heated from the temperature T1 to boiling using the energy Q.

Q = c * m * dT, hence:

m = Q / (c * dT) = Q / (c * (T2 – T1)) = 672 * 10 ^ 3 / (4200 * (100 – 20)) =

= 672 * 10 ^ 3 / (4200 * 80) = 672000/336000 = 2 kilograms.

Answer: the mass of the liquid is 2 kilograms.