1. a Describe what is happening to a sample of material undergoing the following changes of phase:
- i vaporising
ii condensing
iii freezing
iv melting
2. b The following table lists some changes of phase for a sample of material. Complete the table to show what happens to the average kinetic energy ( EK ) and the potential energy ( EP ) of the sample's atoms and molecules: use the phrases, *increases*, *stays the same* or *decreases*.