1. - Everything is made up of matter. ( Living or non-living things )
- r.t.p = room temperature and pressure
 how matter change from one state to another
- Symbols :
S -> solid
ℓ -> liquid
g -> gas
aq -> substance dissolved in water
- Matter can exist in solid, liquid or gas. ( States of matter )
Eg. Water ( liquid ) , ice ( solid ) , vapour ( gas ) .
- Change in temperature and pressure cause change in state.
Property Solid Liquid Gas
Shape Fixed Not fixed Not fixed
Volume Fixed Fixed Not fixed
Compressibility Cannot Cannot Can
- Vapour : given off by liquid even when not boiling
: What we breathe
: exist in r.t.p.
- Kinetic Particle Theory : All matter is made up of tiny particles and that these particles are in
constant , random motion . ( Moving = have kinetic energy )
- Solid state
 Particles closely packed in orderly pattern
 Why have fixed shape?
Particles held together by strong forces of attraction so cannot move about freely . They
only have enough energy to vibrate and rotate on their fixed positions .
 Why have fixed volume ?
Solid cannot be compressed since particles already very close to each other .
- Liquid state
 More space between particles
 No fixed shape because ?
Forces of attraction between particles are weaker , so particles not held in fixed
positions . They are arranged in a disorderly manner and can move freely by sliding over
one another .
Particles more kinetic energy than particles in solid .
 Why have fixed volume ?
Particles farther away from one another than particles in solid but still packed quite
closely together so cannot be compressed .
- Gaseous state
 Particles spread far apart due to very weak force of attraction
 Why do not have fixed shape ?
Have a lot of kinetic energy and are not held in fixed positions . They can move about
rapidly in any direction .
 Why do not have fixed volume ?

2. Between particles have a lot of space , thus allowing gas to be easily compressed when
pressure applied . Particles can be forced to move closer together so can be compressed
and thus no fixed volume .
- Changes of state are reversible .
Eg. On boiling , water back to water vapour . On cooling , water vapour back to water
(liquid) .
- More kinetic energy = higher energy content ( gas is highest )
- Evaporation
Liquid to gas below boiling point
Particles enough energy to escape as a gas from surface of liquid
Liquids that evaporate quickly at room temp. are volatile ( boiling points above room
temp. )
- Condensation
Gas cooled efficiently , changes into liquid
When water vapour touches cold surface , condensation occurs and liquid water is
obtained
Reverse of boiling , heat energy is given out
As temp. drops , particles lose energy and move more slowly until they become liquid
- Sublimation
Shortcut without liquid to become gas from solid
Solids change directly into a gas without going through the liquid state
Occurs because particles at surface of solid have enough energy to break away from
solid and escape as gas
Substances that sublime can also from a gas into a solid without liquid state
( condensation )
Diffusion
- Smell spread when tiny gas particles escape from liquid surface and move around freely until
they reach your nose and is detected as aromas . This proves that particles move freely and
fill up any available space.
- Diffusion is process by which particles move freely and fill up any available space.
- Particles of gas when in confined area , is evenly spread out .
- Different mass / size of particles diffuse at different rates .
Effect of Molecular Mass On Rate of Diffusion
- Mass of gas particle is molecular mass
- Lower molecular mass ( lighter ) diffuse faster than higher molecular mass ( heavier )
Diffusion in liquids / gases

3. - Diffusion is the movement of particles from a region of higher concentration to a region of
lower concentration
Effects of temperature on rate of diffusion
- Rate of diffusion increases as temperature of solution increases
- Higher the temp. , faster the rate of diffusion
- Particles gain more heat as temp. increases and move faster , thus increasing the rate of
diffusion