(3) Changes in State and the Particle Model

Question 1

Equation for density

Answer 1

Density = mass/ volume
(P=m/v)
Density= kg/mᶟ Mass= kg Volume= mᶟ

Question 2

What are the 3 states of matter in order of density?

Answer 2

Least dense
1. Gas
2. Liquid
3. Solid
Most dense

Question 3

Describe a solid in terms of structure, movement and energy

Answer 3

The particles in a solid:
- are tightly packed together and vibrate in fixed positions
- they are all the same size and are in a regular pattern
- they have the least energy out of the other states

Question 4

Describe a liquid in terms of structure, movement and energy

Answer 4

The particles in a liquid:
- are packed together but with enough space to slide past each other
- they are in a random arrangement
- they have a medium amount of energy

Question 5

Describe a gas in terms of structure, movement and energy

Answer 5

The particles in a gas:
- are separate and can move freely, they move in random directions
- they are in a random arrangement
- they have the most energy out of the states of matter

Question 6

What kind of change is changing states?

Answer 6

Changing states is a physical change so you don’t end up with a new substance and it can be easily reversed (the mass is conserved)

Question 7

What is sublimation?
What is reverse sublimation?

Answer 7

• Sublimation is when a solid changes into a gas
• Reverse sublimation is when a gas changes into a solid
  (The opposite)

Question 8

What is evaporation?
What is condensation?

Answer 8

• Evaporation is when a liquid changes into a gas
• Condensation is when a gas changes into a liquid

Question 9

What is melting?
What is freezing?

Answer 9

• Melting is when a solid changes into a liquid
• Freezing is when a liquid changes into a solid

Question 10

When water boils in an open pan, why does the mass appear to decrease?

Answer 10

Some of the water will evaporate and turn into water vapour