To heat a substance weighing 10 kg at 10 ° C, 420 kJ of energy was required. What substance was heated?

Given:

m = 10 kilograms is the mass of some substance;

dt = 10 ° Celsius – the temperature at which the substance was heated;

Q = 420 kJ – the energy expended to heat the body.

It is required to determine which substance was heated.

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

Q = 420 kJ = 420 * 103 = 420,000 Joules.

Let’s find the specific heat of a substance:

c = Q / (m * dt) = 420,000 / (10 * 10) = 420,000 / 100 = 4200 J / (kg * C).

From the table we find that this specific heat corresponds to water.

Answer: the heated substance is water.