Page 124 - Knowledge Organiser Yr7 24-25

4. Melting and Boiling Points
4.1
What is meant by the melting point of a substance?
The temperature at which a substance changes from a solid to a liquid (or liquid to a solid).
4.2
What is meant by the boiling point of a substance?
The temperature at which a substance changes from a liquid to a gas (or gas to a liquid).
3. Changes of State
3.1 How can you change the state of a substance?
3.2 Are changes of state reversible or irreversible changes?
By heating or cooling it.
Reversible.
3.3
Name the changes of state that occur in substances when they are heated and cooled.
heat
cool
3.4
What effect will heating have on the arrangement of particles in a substance?
Particles gain energy, move more and overcome the forces of attraction
3.5
What effect will cooling have on the arrangement of particles in a substance?
Particles lose energy, move less and the forces of attraction become stronger
4.3 What is the melting point of water?
4.4 What is the boiling point of water?
4.5 What temperature is room temperature?
0oC
100oC
20oC to 25oC
5. Diffusion
5.1
What is diffusion?
The movement of particles from an area of high concentration to an area of low concentration until they are evenly spread out.
5.2
In which states of matter can diffusion occur? Why?
Liquids and gases, because the particles are able to move around each other.
5.3
In which state of matter will diffusion occur the fastest?
Gas.
5.4
Draw a diagram to show the diffusion of a substance in a gas.
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Knowledge Base: Science 7.2 Particles Year 7