C1: Particles and Changing State

Question 1

Can you compress a solid?

Answer 1

No

Question 2

Does a solid have a ‘fixed shape’?

Answer 2

YES

Question 3

Can you see the particles that make up materials?

Answer 3

No - they are too small to see.

Question 4

Can you compress a gas?

Answer 4

Yes - because its particles are far apart

Question 5

What is meant by the properties of a material?

Answer 5

The features of the material e.g. is it strong

Question 6

Identify the 3 states of matter.

Answer 6

Solid

Liquid

Gas

Question 7

Does a liquid have a fixed shape?

Answer 7

No - liquids can take the shape of the container that they are poured into.

Question 8

Does a liquid flow? (can it be poured?)

Answer 8

Yes- because its particles can roll around each other.

Question 9

Describe the particles in a solid.

Answer 9

Neatly arranged

Vibrating

All touching

Question 10

What is a mixture?

Answer 10

A mixture is something that is made from lots of different types of particles e.g. air is a mixture of different particles.

Question 11

Which state is shown below?

Answer 11

Liquid

Question 12

Which state is shown below?

Answer 12

Gas

Question 13

Does a gas have a fixed shape?

Answer 13

No - they can take the shape of the container that they are in e.g. a balloon

Question 14

What is matter?

Answer 14

The ‘stuff’ that everything is made from.

Question 15

We say that all materials are made from tiny pieces called…

Answer 15

……particles

Question 16

Describe the particles in a liquid.

Answer 16

Not an orderly arrangement

Moving around one another

Mostly touching

Question 17

Which state is shown below?

Answer 17

Solid

Question 18

Describe the particles in a gas.

Answer 18

Randomly arranged

Moving around

Not touching

Question 19

Can you compress a liquid?

Answer 19

No - its particles are too close together.

Question 20

What is meant by a state?

Answer 20

Whether something is a solid, liquid or gas.

Question 21

Melting and freezing are both examples of…

Answer 21

changes of state

Question 22

You are given 3 unknown solids.

Describe how you could identify the substances by using their melting points.

Answer 22

Heat each substance until they melt and record their melting points.

Look up the melting points of different solids on the internet.

Compare your melting point to the ones from the internet to identify the substance.

Question 23

When a substance changes from a liquid to a solid we call it…

Answer 23

……freezing

Question 24

When a substance changes from a solid to a liquid we call it…

Answer 24

……melting

Question 25

What is meant by the **_melting point_** of a substance?

Answer 25

The temperature that a substance begins to melt at.

Question 26

What temperature does ice begin to melt at?

Answer 26

0 °C

Question 27

Describe what happens to water paricles when an ice cube melts.

Answer 27

1. Water particles in ice are close and neatly arranged. 2. The particles vibrate on the spot. 3. As the particles in ice gain energy, they vibrate more and more. 4. This happens until eventually bonds between the particles begin to break. This is called melting. 5. The particles start to move about as a liquid.

Question 28

What temperature does water boil at?

Answer 28

100 ºC

Question 29

What do we call it when a gas turns into a liquid?

Answer 29

Condensation

Question 30

What is boiling?

Answer 30

When a substance is changing from a liquid to a gas state (evaporates) at its fastest rate

Question 31

How do we make a substance boil?

Answer 31

We need to give enough **_thermal energy_** (heat) to its particles.

Question 32

If the temperature of a gas falls below its boiling point, what will happen?

Answer 32

It will condense back into a liquid

Question 33

What is evaporation?

Answer 33

When some particles in a liquid gain enough energy to escape from its surface. This is different to boiling!

Question 34

What is the difference between boiling and evaporation?

Answer 34

Evaporation happens at any temperature boiling happens only at the boiling point. Evaporation is where particles escape from the **_surface_** of a liquid, boiling is where gas bubbles form **_throughout_** the liquid , rise and then escape,

Question 35

Use ideas about particles and evaporation to explain why sweating cools you down.

Answer 35

1. Sweat comes out of the pores in your skin. 2. Water from the sweat evaporates. 3. The water particles need energy to move away as a gas. 4. They take this energy from your skin, which cools you down.