Classifying materials- particle theory

Question 1

Identify the three states of matter?

Answer 1

Solid
Liquid
Gas

Question 2

Which has the strongest attraction between particles, solid, liquid or gas?

Answer 2

Solid the strongest, then liquid, then gas

Question 3

Which have their particles in fixed positions, solid, liquid or gas?

Answer 3

Only solids

Question 4

Which have particles which vibrate, but do not move solid, liquid or gas?

Answer 4

Solid

Question 5

Which have particles which constantly move solid, liquid or gas?

Answer 5

Liquid and gas

Question 6

Which have particles which keep the same volume, solid, liquid or gas?

Answer 6

Solid and liquid but not gas

Question 7

Which have particles which keep the same shape, solid, liquid or gas?

Answer 7

Only solid

Question 8

Which have particles which can be compressed solid, liquid or gas?

Answer 8

Gases can be compressed easily because of the large space between the molecules
Liquids don’t compress easily because of the small space between the molecules
Solids cannot be compressed because they are tightly packed

Question 9

Put solids liquids and gases in order of their density starting with the most dense.

Answer 9

Solid
Liquid
Gas

Question 10

Describe what is meant by density in terms of particles

Answer 10

The more particles there are in a specific volume the denser the substance.

Question 11

The particles of which move the fastest, solid, liquid or gas?

Answer 11

Gas particles whizz about
Liquid particles move more slowly
Solid particles do not move but vibrate.

Question 12

When particles of gas hit a surface they cause what?

Answer 12

Gas pressure

Question 13

The more gas particles hit a surface the harder they hit it and the faster they move the higher the gas pressure in a container, explain two ways you can increase the gas pressure in a container

Answer 13

1. Increase the temperature- this makes the particles move more quickly and hit harder and more often
2. Decrease the volume of the container - the particles will hit the sides more often

Question 14

Explain how the movement of particles of gas in a container causes gas pressure.

Answer 14

1. The gas particles hit the sides of the container which causes gas pressure.

Question 15

High gas pressure is cause by particles doing what?

Answer 15

Hitting the walls of the container often
Hitting the walls of the container hard

Question 16

Explain diffusion in terms of particles

Answer 16

Diffusion is the movement of particles throughout a space.

Question 17

Explain how the smell of a cake cooking moves through the house

Answer 17

The smell particles are highly concentrated in the oven, when the door is opened they move out into the kitchen by diffusion.
The smell particles spread slowly through the house as they keep bumping into the air particles and changing direction.
Eventually the smell particles spread from the house to outside and you cannot smell the cake anymore.

Question 18

When a substance changes from a solid to a liquid it is known as?

Answer 18

melting

Question 19

When a substance changes from a liquid to a solid it is known as?

Answer 19

freezing

Question 20

It’s rare but a solid can change directly from a solid to a gas- this is called

Answer 20

sublimation/subliming

Question 21

The temperature a substance changes from a solid to a liquid it is known as?

Answer 21

melting point

Question 22

What is the melting point of solid water (ice)

Answer 22

0 degrees Celcius

Question 23

What is the freezing point of water

Answer 23

0 degrees Celcius

Question 24

What is the boiling point of water

Answer 24

100 degrees Celcius

Question 25

When a substance changes from a gas to a liquid it is known as?

Answer 25

condensing

Question 26

When a substance changes from a liquid to a gas it is known as?

Answer 26

Boiling or evaporation

Question 27

The temperature a substance changes quickly from a liquid to a gas is known as?

Answer 27

Boiling point

Question 28

When a substance is heated do the particles gain or lose energy?

Answer 28

Gain-

Question 29

Explain what happens to the particles when a solid is heated

Answer 29

1. The particles gain more energy
2. The more energetic particles vibrate more which weakens the bonds holding them together
3. At a certain temperature they have enough energy to break free from their position and become a liquid- melting point

Question 30

Explain what happens to the particles when a liquid is heated

Answer 30

1. The particles gain more energy
2. The more energetic particles move faster, which weakens the bonds holding them together
3. At a certain temperature they have enough energy to break the forces and become a gas - boiling point

Question 31

What is the difference between evaporation and boiling?

Answer 31

Both describe the change in state from a liquid to a gas but evaporation happens slowly and at any temperature, boiling happens quickly at a specific temperature

Question 32

Does a substance usually expand or contract when heated?

Answer 32

Most substances expand

Question 33

Explain why a substance expands when heated

Answer 33

The particles move more and become further apart so the substance is less dense and expands

Question 34

Explain why a substance contracts when cooled

Answer 34

The particles move less and become closer so the substance is less dense and expands

Question 35

Does a substance usually expand or contract when cooled?

Answer 35

Most substances contract- ice is different though!

Question 36

Explain the difference between a chemical change and a physical change?

Answer 36

During a physical change there is no reaction so the mass stays the same it’s just that the particles have more or less energy so are rearranged differently.
During a chemical change there is a chemical reaction and new products are formed.

Question 37

Explain how a mercury or alcohol thermometer can show us a specific temperature

Answer 37

As the temperature increases the mercury or alcohol expands and moves up the tube it is held in. As it decreases it contracts and moves down.
The amount of contraction or expansion at a certain temperature is always the same so can be marked on a scale.