Particle Theory

Question 1

Solid

Answer 1

Strong forces between particles
Fixed position
Vibrate around their position

Question 2

Liquid

Answer 2

Weak forces between particles
Randomly arranged
Have a definite volume
No definite shape
Particles constantly moving randomly

Question 3

Gas

Answer 3

Very weak forces between particles
No definite shape of volume
Can fill any container
Move constantly in a random motion
When heated they expand - pressure increases

Question 4

Solid to liquid

Answer 4

Melting

Question 5

Liquid to gas

Answer 5

Evaporating

Question 6

Gas to liquid

Answer 6

Condensing

Question 7

Liquid to solid

Answer 7

Freezing

Question 8

Solid to gas

Answer 8

Subliming

Question 9

Diffusion

Answer 9

Gradual movement of particles from places with lots of particles to places with fewer

• much slower in a liquid than air

Question 10

Potassium manganate and water

Answer 10

Fill a beaker with water
Place potassium at bottom
Purple colour slowly spreads out to fill beaker

Question 11

Ammonia and hydrogen chloride

Answer 11

NH3 diffuses from one end of the tube
HCL diffuses from the other
When they meet they form Ammonia Chloride
A ring forms nearest to HCL end
This is because Ammonia diffuses faster than HCL

Question 12

Bromine gas and air

Answer 12

Bromine gas is brown and strong smelling
Fill half a gas jar with bromine
Fill the other with air
Separate the gases with a glass plate
Remove glass plate - you see Bromine gas diffusing
Random motion of particles means Bromine will eventually diffuse right through air