What mass can be heated by 20 C if 5 kJ of heat is consumed?

dt = 20 ° Celsius – the temperature to which it is necessary to heat the water;

Q = 5 kJ – the amount of heat consumed for water heating;

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

It is required to determine m (kilogram) – how much water can be heated with heat equal to Q.

Let’s translate the units of measurement of energy into the SI system:

Q = 5 kJ = 5 * 10 ^ 3 = 5 * 1000 = 5000 Joules.

Then, the mass of water can be determined from the following formula:

Q = c * m * dt, from here we find that:

m = Q / (c * dt) = 5000 / (4200 * 20) = 5 / (42 * 2) = 5/84 = 0.06 kilograms (the result has been rounded to one hundredth).

Answer: You can heat water weighing 0.06 kilograms.