1.
The change from gas to liquid.
2.
The change from solid to liquid.
3.
The change from a liquid to gas.
4.
The change from liquid to solid.
Column B
a.
Requires the removal of heat. This slows down the particles, so the kinetic energy of the particles decreases. The particles move closer together as attractive forces between the particles get stronger.
b.
Requires the addition of heat energy. This weakens the attractive forces between particles. The molecules start to move faster as their kinetic energy increases. The particles move away from each other as the kinetic energy overcomes the forces of attraction.
1. The change from gas to liquid. (b)
2. The change from solid to liquid. (b)
3. The change from a liquid to gas. (a)
4. The change from liquid to solid. (a)