Physics Chapter 3

Particle model of matter

Describe the state of matter of a solid?

• Packed closely together
  - Fixed shape
  - Fixed position
  - Can only vibrate
  - Strong forces of attraction
  - Has a regular arrangement

Describe the state of matter of a liquid?

• Weaker forces of attraction
  - No fixed position
  - Fixed shape
  - Particles close together but can move past each other
  - Move at random directions at a low speed
  - Particles have more energy than solids

Describe the state of matter of a gas?

• Almost no forces of attraction
  - No fixed shape or fixed position
  - Particles move in random directions at a range of speeds
  - Free to move
  - More energy than solids and liquids

Order the states of matter in terms of density? (Least dense to Most dense)

Gases, Liquids, Solids

What makes a material dense?

If its particles are packed tightly together. If it was less dense, the materials' particles will be more spread out

How can I make a less dense material more dense?

Compressing the material. You wouldn't be changing the mass, but you would be decreasing the volume
.The particles will move closer together, becoming denser.

Which state of matter is easily cmpressible and why?

Gases.
The gas particles are already very spread out meaning you can squash the gas into a smaller volume
Essentially, reducing distance between particles
Particles in liquids & solids can't get much closer together

Why is a change of state a physical change and not a chemical change?

If the change is reversed, the substance recovers its original properties
It doesn't produce a new substance therefore mass is conserved

How to find density of an irregular solid?

Fill an euraka can with water and allow excess to drip out
Put an irregular object into the water
Measure the volume of water displaced using a measuring cylinder (V)
Find Mass using mass balance (M)

D = M/V

How to find density of regular solid? (easy)

Find mass of solid using the balance
Measure the solid's three lengths and calculate volume (V = L x W x H)
Calculate density - D = M/V

What is specific latent heat of vaporisation?

The energy required to change the state of 1kg of substance from liquid to gas

What is the specific latent heat of fusion?

The energy required to change the state of 1kg of substance from solid to liquid

What is specific heat capacity?

The energy required to raise the temperature of 1kg of substance by 1 degrees celcius

What is internal energy?

Total kinetic and potential energy particles have in a system

What does heating a system cause?

A change in state

An increase in temperature

What does the size of temperature change depend on?

Type of material

Mass of material

Amount of energy supplied

When a substance changes state, what also changes and what doesn’t?

Does - Energy transferred

Doesn’t - Temperature of it