1.
There are three states of matter; solids, liquids and gases.
Below we have given certain characteristics - can you tell which state of
matter they relate to?
b.
This
state of matter does not have a definite shape or volume.
c.
Particles vibrate but they have fixed positions.
d.
This
state of matter has a definite volume but not a definite shape.
e.
Particles are close
together and move relative to each other.
f.
Particles are far apart
from each other and there are no forces of attraction between
particles.
g.
The particles are
closest together in this state of matter.
h.
This state of matter has
a definite shape and volume and is hard to compress.
i.
This state of matter
does not have a definite shape but is hard to compress.
j.
This state of matter
does not have a definite shape and is east to compress.
k.
Above its boiling point
a substance is a ……….
l.
Between its melting
point and boiling point a substance is a ………
m.
Below its melting point
a substance is a ……..
n.
Particles within which
state of matter move fastest?
o.
Particles within which
state of matter move slowest?
Particle Theory
Diffusion
The movement of particles is called Diffusion. Gases diffuse quickly
because the particles are moving quickly in all directions. Another
definition of Diffusion is the movement of particles from an area of
high concentration to areas of low concentration.
Consider how perfume or aftershave works. Initially particles of the
perfume are sprayed into the air. Because the perfume and the air are
both gases, the particles are moving very fast and bumping into each
other. This causes the particles to move further in all different
directions and hence the smell (perfume particles) to diffuse through
the air all the way to your nose which is when you smell the perfume.
Expansion
When particles are heated, they become more active and move around more. It is
important to note that the particles do not become larger themselves; they just
take up more space as they are moving around a lot more. This is why all states
of matter expand upon heating.
The degrees of expansion are dependent on the specific state. For example,
solids will expand the least because the particles are held quite tightly
together. Liquids will expand more than solids but Gases will expand the most.
When cooled, substances contract and become smaller.
Expansion can exert a lot of force and in hotter countries this is taken into
account when building. For example concrete roads are built with gaps in them to
allow expansion in hot weather.
Gas Pressure
Gas particles move very quickly in all directions. If gas is in a container
these gas particles will crash into the walls and this force creates gas
pressure. If the temperature increases so does the activity of the gas particles
and hence the gas pressure also increases.
Questions
1) What is the movement of particles called?
2) How can you smell perfume?
3) Why do gases diffuse quickly?
4) What causes pressure?
5) Can liquids diffuse?
6) What happens to particles when they are heated?
7) Why is there an increase in pressure as the temperature increases?
8) On heat, do the particles expand themselves?
scroll
down for answers
1. Diffusion
2.
Scent molecules form the perfume diffuse through the air to your nose.
3.
Gas particles move quickly in all directions allowing gases to diffuse quickly.
4.
Pressure is created when gas particles crash into the walls of the container they are held in.
5.
Liquids can diffuse but they diffuse slower than gases.
6.
Particles move around more when they are heated.
7.
An increase in temperature leads to an increase in activity by the particles and
causes them to crash into the walls of the container more and hence increases
the pressure.
