What is the change in thermal energy of the gas during this process?

Question

A gas is compressed from 600 cm^3 to 200 cm^3 at a constant pressure of 400 kPa. At the same time, 100 J of heat energy is transferred out of the gas.

Answer 1

600cm^3 = 6x10^(-4) m^3
200cm^3 = 2x10^(-4) m^3
Remember 1 Pa = 1 N/m^2, and 1 J = 1 N*m
The work done (by gas) for the volume change:
(2x10^(-4) m^3 - 6x10^(-4) m^3)*400kPa
= -160 J
Heat transfer: 100 J
the change in thermal energy of the gas during this process is -60 J.