When a substance is in the gas state, the particles are spread out far apart from each other. There is a lot of space between particles in a gas.
As particles in a gas move to fill the container they are in, gases do not have a fixed volume.
The table below gives a summary of the properties of solids, liquids and gases:
Does the
substance have a fixed mass?
Solid
Liquid Gas
Yes Yes Yes
Compressing gases
We know that particles in a gas have lots of space between them. Compression happens when the particles are pressed together to make them fit into a smaller space. For example, the gas particles in a spray can of deodorant or hairspray are pressed together to fit into the can. When the contents of the can are sprayed, the particles can spread out again to fill the air.
Does the
substance have a fixed volume?
Yes Yes No
Does the
substance have a fixed shape?
Yes No No
: Fig. 14.5 Particles in a gas state
Does the substance flow?
No Yes Yes
Can you
compress the substance easily?
No No Yes
) Fig. 14.6 Compression of a gas to a liquid
? TEST TUBE
3. In which state is a substance if it: a. has a fixed volume and a fixed shape b. can flow and can be compressed c. has a fixed volume and can flow d. takes the shape of the container it is placed in e. does not flow and cannot be compressed?