Question

A piston uses 32 J of energy to do work as 68 J of heat are added to the cylinder of the piston. The change in internal energy of the system is____J.

Answer 1

Internal energy is defined as the energy associated with the random, disordered motion of molecules. It is denoted by U and  calculated by the expression:

ΔU = Q - W

We calculate as follows:

ΔU = 68 J - 32 J

ΔU = 36 J

and answer is 36 J