Changing State
Science: KS3, topic 2.1.9
Changing State - Processes
There are 4 processes that can cause a substance to change state:
Boiling
- Liquid → gas.
Melting
- Solid → liquid.
Freezing
- Liquid → solid.
Condensing
- Gas → liquid.
Melting and Boiling Points - Forces Between Particles
The amount of energy required for substances to change state depends on the strength of the forces between their particles.
Strong forces
- Strong forces between particles means lots of energy is needed to overcome them.
- Substances with strong forces between particles have high melting and boiling points.
Weak forces
- Weak forces between particles means little energy is needed to overcome them.
- Substances with weak forces between particles have low melting and boiling points.
Test yourself on Changing State
What is another name for the process of boiling, when a liquid changes into a gas?
Name the processes that lead to a change in state
Why does a solid melt when it's heated to its melting point?
A block of ice is heated past its melting point and then past its boiling point. Name the three states of matter it passes through.
Which of the following is true for a solid with a high melting point?