1. Messano Maria/Bonazzi Enrico

2. Matter is made up of atoms or molecules. Around 400BC Democritus put forward his ideas about particles.

3. Messano Maria/Bonazzi Enrico The arrangement of these particles determines the state of matter.

4. Messano Maria/Bonazzi Enrico Scientists have identified three main states of matter in the environment of the Earth solid liquidgas

5. Messano Maria/Bonazzi Enrico We know that wood is a solid, that water is a liquid, and that air is a gas.

6. Messano Maria/Bonazzi Enrico Solids, liquids and gases can easily be recognized by their different properties.

7. Messano Maria/Bonazzi Enrico Solids have a fixed volume and shape. The solid state In a solid the particles are held very close together so they can hardly move.

8. Messano Maria/Bonazzi Enrico Solids have their own shape stay where they are put are difficult to pass through can't be compressed (squashed)

9. Messano Maria/Bonazzi Enrico The Liquid State In a liquid, the particles are not so tightly packed, so they can move a little. Liquids have a fixed volume but take the shape of the container they are in.

10. Messano Maria/Bonazzi Enrico Liquids take the shape of their container can be poured are quite easy to pass through are very difficult to compress

11. Messano Maria/Bonazzi Enrico The Gaseous State Atoms in a gas are spread apart and can move easily. Gases have indefinite volume and indefinite shape ( they expand to fill all available space).

12. Messano Maria/Bonazzi Enrico Gases take the shape of the whole container spread out quickly are very easy to pass through are easy to compress

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14. CHANGE IN STATE All matter can move from one state to another. The chemical properties of materials are unchanged when the state changes. State changes of matter are physical rather than chemical changes.

15. Messano Maria/Bonazzi Enrico Water can be solid - we call it ice.

16. Messano Maria/Bonazzi Enrico Water can be liquid - we call it water

17. Messano Maria/Bonazzi Enrico Water can be a gas - we call it water vapour. Don't get mixed up : Steam, e.g. from a kettle, is a mixture of water droplets and water vapour. water vapour water droplets

18. Messano Maria/Bonazzi Enrico Changing states of matter is about changing densities, pressures, and temperatures. The basic chemical structure does not change.

19. Messano Maria/Bonazzi Enrico State changes happen when certain points are reached.

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21. MELTING POINT When a solid reaches the temperature of its melting point, it can become a liquid. There is a “magic temperature” for every substance called melting point.melting point Molecules in a liquid have more energy than the atoms in a solid.more energy

22. Messano Maria/Bonazzi Enrico MELTING POINT BOILING POINT

23. Messano Maria/Bonazzi Enrico CHANGE IN TEMPERATURE freezing freezing point melting point melting solid condensing condensation point boiling point liquid evaporating gas

24. Messano Maria/Bonazzi Enrico Condensation is the change from a gas to a liquid. Freezing or Solidification is the change from a liquid to a solid. Boiling is the change from a liquid to a gas. Melting is the change from a solid to a liquid.

25. Messano Maria/Bonazzi Enrico Sublimation is either the change from a solid directly to a gas, or the change from a gas to a solid. Sublimation Solid Gas Liquid Solidification Melting or freezing Condensation Vapourization

26. Messano Maria/Bonazzi Enrico Density The mass of matter divided by its volume. Shape Is it fix or take the shape of the container?

27. Messano Maria/Bonazzi Enrico Compressibility If we apply pressure, does the volume decrease? Thermal expansion How much does the volume change when heated?

28. Messano Maria/Bonazzi Enrico EXPERIMENT MELTING POINT Take a 600 ml beaker and put 450 ml of water into it. This is a water bath. Put a thermometer into the test-tube. Put the test-tube into the beaker. Put some stearic acid into a test-tube. You have to fill the bottom of the test tube. Turn on the gas and start measuring the temperature every 20 sec., while stirring the water with a stick. Note down the values. When the water starts boiling note down the values and draw a graph (heating curve)

29. Messano Maria/Bonazzi Enrico Label your graph to show where stearic acid is a solid, a liquid, or present in both states. What is the melting point of stearic acid? QUESTIONS

30. Messano Maria/Bonazzi Enrico Reference material in English on the internet: www.chem.purdue.edu www.nyu.edu www. bbc.co.uk www. 2.mcdaniel.edu www. idahoptv.org www.chem4kids.com www.chemistryforyou.co.uk