1.2 Physical and chemical changes

• Kinetic theory of matter
• Heating curve
• Effects of impurities on boiling point and melting point
• Physical and chemical changes, both temporary and permanent
• Applications of physical and chemical changes in day-to-day life

• describe the characteristics of particles in the three states of matter
• explain the effects of impurities on the boiling point and melting point of a substance
• distinguish between physical and chemical changes in substances
• outline applications of change of state of matter in day-to-day life
• appreciate the applications of change of state of matter in day-to-day life

“How does the movement of particles in matter affect its properties?”

The titles are open to everyone. Reading a lesson needs an account — sign in or create one.

1. The three states of matter
   40 min · 1 practice tasks · quiz
   Solid, liquid and gas compared by shape, volume, particle spacing and movement.
2. Particles in a solid
   40 min · 1 practice tasks · quiz
   Why a solid keeps its shape, cannot be poured and cannot be squashed.
3. Particles in a liquid
   40 min · 1 practice tasks · quiz
   Why a liquid flows and takes the shape of its container, yet keeps its volume.
4. Particles in a gas
   40 min · 1 practice tasks · quiz
   Why a gas fills any container, spreads on its own and can be squashed.
5. The kinetic theory of matter
   40 min · 1 practice tasks · quiz
   The three statements that explain the states of matter, and what temperature really measures.
6. Diffusion in liquids
   40 min · 1 practice tasks · quiz
   Watching ink spread through still water, and what it proves about particles.
7. Diffusion in gases
   40 min · 1 practice tasks · quiz
   How a smell crosses a room, and why diffusion is so much faster in a gas.
8. What heating does to particles
   40 min · 1 practice tasks · quiz
   Following the energy from the flame into the particles, and what happens when they break free.
9. Melting and freezing
   40 min · 1 practice tasks · quiz
   Two changes of state at the same temperature, and why the thermometer stops while ice melts.
10. Boiling and condensing
    40 min · 1 practice tasks · quiz
    Bubbles forming throughout a liquid, steam turning back to water, and why altitude changes the boiling point.
11. Evaporation and sublimation
    40 min · 1 practice tasks · quiz
    Drying without boiling, what makes it faster, and the change that skips the liquid stage.
12. Drawing a heating curve
    40 min · 1 practice tasks · quiz
    Recording temperature against time as ice is heated all the way to steam, and plotting the result.
13. Reading the flat sections
    40 min · 1 practice tasks · quiz
    Why the temperature stops rising while heating continues, and what the energy is doing instead.
14. Melting points and boiling points
    40 min · 1 practice tasks · quiz
    The fixed points of common substances, and how they decide what state something is in.
15. Finding a melting point
    40 min · 1 practice tasks · quiz
    The water bath method, what to record, and the safety rules that go with a flame.
16. Impurities and melting point
    40 min · 1 practice tasks · quiz
    How adding something else lowers the melting point and turns a sharp value into a range.
17. Impurities and boiling point
    40 min · 1 practice tasks · quiz
    The opposite effect at the other end, and an honest look at how large it really is.
18. Using the impurity effects
    40 min · 1 practice tasks · quiz
    Four real uses of lowering a freezing point and raising a boiling point.
19. What a physical change is
    40 min · 1 practice tasks · quiz
    Changes where no new substance is made, and why they are called temporary.
20. What a chemical change is
    40 min · 1 practice tasks · quiz
    Changes that make a new substance, the signs to look for, and why they are permanent.
21. Telling the two apart
    40 min · 1 practice tasks · quiz
    One question that sorts any change out, and the tricky cases that need care.
22. Changes of state in daily life
    40 min · 1 practice tasks · quiz
    How preserving, purifying and cooling all depend on the changes of state you have learnt.