foundation (chapter 1).pdf(state of matter)

pre-igcse level

1. Chapter 1
States Of Matter
•Everything around us made up of matter. Living things like your pet cat even made up of matter.
Non-living things such as a roll of film, popcorn and dust are made of matter too.
•Have you ever seen dust dancing in the light?

2. 1.1 States Of Matter
•Matter can exist as a solid, a liquid or a gas. There are three forms of matter are called the states of
matter . For example, water can exist as solid (ice) , liquid (water) or gas (water vapour).
•Most substances can exist in each of the three states of matter .
•Matter can change from one state to another due to changes in temperature and pressure.

5. Properties of solids, liquids and gases
•Solids –relatively rigid, definite volume and shape. In a solid, the atoms and molecules are
attached to each other. ...
•Liquids –definite volume but able to change shape by flowing. In a liquid, the atoms and
molecules are loosely bonded. ...
•Gases –no definite volume or shape.

6. Toindicatethestateofasubstance,weusethestatesymbol“s”forsolid,“l”forliquidand“g”forgasorvapour.
Thestatesymbol“aq”isusedforsubstancesdissolvedinwater.Thestatesymboliswrittenwithinbracketsand
placedaftertheformulaofthesubstance.

7. 1.2 Kinetic Particle Theory
•The kinetic theory states that all matter is made up of tiny particles
and that they have kinetic energy , hence the name kinetic particle
theory.
•The kinetic particle theory can (i) describe the states of matter
(ii)explain the differences in the properties of solids, liquids and gases
and (iii) explains the changes of state.

8. The states of matter

9. The Solid State
•In solids, particles are tightly or closely packed.
•The gaps between the particles are tiny and hence it is tough to compress them.
•Solid has a fixed shape and volume.
•Due to its rigid nature, particles in solid can only vibrate about their mean position
and cannot move.
•Force of attraction between particles is adamant.
•The rate of diffusion in solids is very low.
•An example of solids: solid ice, sugar, rock, wood, etc.

11. The Liquid State
•In a liquid state of matter, particles are less tightly packed as compared to solids.
•Liquids take the shape of the container in which they are kept.
•Liquids are difficult to compress as particles have less space between them to
move.
•Liquids have fixed volume but no fixed shape.
•The rate of diffusion in liquids is higher than that of solids.
•Force of attractionbetween the particles is weaker than solids.
•Example of a liquid state of matter: water, milk, blood, coffee, etc.

12. Liquids

13. The Gaseous State
•In gases, particles are far apart fromeach other.
•Force of attraction between the particles is negligible, and they can move freely.
•Gases have neither a fixed volume nor a fixed shape.
•The gaseous state has the highest compressibility as compared to solids and
liquids.
•The rate is diffusion is higher than solids and liquids.
•The kinetic energy of particles is higher than in solids and liquids.
•An example of gases: air,helium, nitrogen, oxygen, carbon dioxide, etc.

15. Changes of States
When states of matter change,
•The state of matter of a substance can be changed .
•This type of change is called a physical change and is a reversible reaction .
•Melting , freezing , evaporating , boiling ,condensing and sublimation all examples of physical
change.

16. Interconversions between the three states of matter
When the substances effects by energy, they change state.
1.Melting (solid to liquid).
•The temperature at which the solid melts is called its
melting point.
2. Evaporation (liquid to gas).
•The temperature at which the liquid boils is called its
boiling point.
3. Freezing (liquid to solid).
•The temperature at which the liquid freezes is called its
freezing point.
4. Deposition (gas to solid).
5. Sublimation (solid to gas).
6. Condensation (gas to liquid).
Melting point= freezing point (at 0˚C)
Boiling point (at 100˚C)
We can describe the state of a substance at room
temperature by looking at its melting and boiling point
Melting point Boiling pointr.t.p
solid gasliquid

17. Melting
•When a solid is heated to its melting point it loses and start to flow .This is due to the energy
supplied by the heat , making the particles vibrate more strongly so they push each other further
away .This weakens the forces of attraction between the particles and allows them to move around
each other.

18. Freezing
•When a liquid is cooled to its freezing point the particles lose so much energy that they can no
longer move around each other . The only movement possible is the vibration to and fro about one
position in a lattice and the liquid becomes a solid.

20. Evaporation
•A liquid can turn into a gas over a range of temperatures without boiling by a process called
evaporation.
•In this process , some of the liquid at the surface changes into a gas and mixes with the air.
•It happens because the particles in a liquid have different amounts of energyand those with the
most energy move the fastest.
•At the surface these fast moving particles break away from the others escape into the air and form a
gas.

21. Boiling
•When a liquid reaches its boiling point bubbles of gas form in it which rise to the surface and burst
into the air.
•This process is called boiling .
•If the boiling liquid is heated more strongly, its temperature does not rise but it boil more quickly.
•The heat makes all the particles in the liquid move more quickly and the fastest moving particles
escape from the surface of the liquid or collect in the liquid to form bubbles which then rise to the
surface and burst into the air .
•These fast moving particles released from the liquid form a gas.

22. Boiling and Evaporation
Boilingis when a liquid changes into a gas .
This occurs below the surface a liquid and requires a
specific temperature which is known as boiling point
(unique to each pure liquid).
Evaporationis when a liquid changes into a gas but it
occurs at the surface only and requires over a range of
temperature below boiling point.
Main difference is that bubblesare present during
boiling process.

23. Differences between boiling and evaporation
•Both boiling and evaporation involve a liquid changing to a gas , but boiling is different from
evaporation in following ways.
Boiling Evaporation
Occurs only at boiling point Occurs at temperatures below boiling point
Occurs throughoutthe liquid Occurs only at the surface of the liquid
Occurs rapidly Occurs slowly
Bubbles are present Nobubbles are present

24. Condensing
•If a gas cools down far enough, it condense and form a liquid.
•The particles in a gas lose some of the energy which allows them to move so quickly and they
slow down so much that they can no longer bounce off each other when they meet .
•They stay close to each other and form a liquid.

25. Sublimation
•A few substance can change from a solid to a gas or a gas to a solid forming a liquid. This process
is called sublimation.
•When the solid changes into a gas , the forcewhich bind the particles together are quickly lost and
they move away from each other completely.
•When a gas forms directly into a solid, the particles lose their energy so quickly that they come
together and are held by the forces between them.

26. Describing the state of a substance
•We can determine the states of a substance by noting the ranges of temperature at which the
substance exits whether solid or liquid and gas.

27. Substances Meltingpointsin˚C Boilingpointsin˚C
W -220 -118
X -101 -34
Y -7 59
Z 114 184
4. (a) Figure 2 shows the melting points and boiling points of four substances, w, X, Y, Z.
Using the information in figure,
•Give the letter of the substance that is a solid at 20˚C.(1mark)
…………………………………………………………………………………………………

28. Diffusion
Diffusionisthespreadingoutparticlesfromwheretheyareathigh
concentrationtowheretheyareatalowconcentration[atacertainvolume].
Diffusionin gases
•Here , we see the diffusion of bromine gas from one gas jar to another .
•After 5 minutes the bromine gas has diffused from the bottom jar to the top jar
.
Explanation
•The air and bromine particles are moving randomly and there are large gaps between particles .
•The particles can therefore easily mix together .

29. Diffusion in gases
•When a bottle of perfume is left open for some time ,the scent of the perfume soon spread
throughout the entire room.
•This is because millions of tiny gas particles escapes from the surface of perfume. These particles
can move around freely until they reach your nose, where they are detected as aromas.
•The spreading of aromas is another observation that proves that particles of gases are constantly
moving .
•The process by which particles move freely to fill up any available space is called diffusion.
•We can demonstrate it in the laboratory.

31. Diffusion in liquids
1.Place a spatula ofpotassium permanganate(or any other strongly colored substance) in a gas
jar full of water, right at the bottom. (note that for best results, use a straw to do this)
2.You will see the purple color is most concentrated at the bottom and very light at the top.
3.Diffusion will happen, as the color eventually evens out. In liquids this is very slow, so leave it
to diffuse over a couple of days
4.When the color has evened out, it has reachedequilibrium.

33. Topic questions
1.How do particles move in a substance in the solid state?
2.Why can a liquid flow?
3.Why can a gas can be compressed?
4.What is the name of the change of state from gas to liquid?
5.In which change is energy transferred from the surroundings to the substance?
6.Why is energy transferred from the substance to the surroundings when a substance freezes?
7.Which two states of matter are involved in sublimation?
8.The stronger the forces of attraction, the higher the melting point. Is this statement true or false?
9.A substance has a melting point of -7°C and a boiling point of 59 °C . What is its state at room
temperature?
10.A substance has a melting point of -210°Cand boiling point of -196°C. What is its state at -
190°C?
11.Which state of matter has particles with the highest energy?
12.What happens during sublimation?
13.What happens to the energy of gas particles when they condense to a liquid?
14.Why are solids difficult to compress?
15.What is diffusion?