1. Explain what changes occur in particle motion, temperature,
and state of a pure substance when thermal energy is added
or removed.
Type your answer here

Thermal energy is heat energy.

When it is removed, the temperature of particle decreases due to decrease in the internal energy involving that particle.

Motion of the particle decreases due to decrease in kinetic energy caused by reduction in the internal energy.

The state of the particle changes from that current state e.g liquid or gas to a solid state due to increase in the latent heat of vapourisation.