Year 9 chemistry

Question 1

Describe particles in a solid

Answer 1

• Strong force of attraction
• Definite shape/volume
• Vibrate in their positions
• Gain energy when heated
• Arranged in rows
• Can’t compress

Question 2

Describe the particles in a liquid

Answer 2

• weak force of attraction
• free to move but fairly compact
• definite volume but can flow
• shape can change to fit into a container
• no arranged position
• when heated they gain energy and move faster

Question 3

Describe the particles in a gas

Answer 3

• force of attraction is very weak/no attraction
• free to move around
• doesn’t keep definite shape/volume
• always fills a container
• constantly moving in random directions and motion

Question 4

What is it called when a solid changes to a liquid?

Answer 4

Melting

Question 5

What is it called when a liquid changes into a gas?

Answer 5

Evaporation

Question 6

What is it called when a Gas turns into a liquid?

Answer 6

Condensation

Question 7

What is it called when a Liquid turns into a solid?

Answer 7

Freezing

Question 8

What is it called when a solid turns into a gas?

Answer 8

Sublimation

Question 9

What is it called when a gas turns into a solid?

Answer 9

Deposition

Question 10

What is an impure substance?

Answer 10

A mixture of 2 or more substances
Melts over a range of temperatures

Question 11

What is a pure substance?

Answer 11

Only consists of one element or compound
Melts at a sharp or defined temperature

Question 12

What is a soluble?

Answer 12

A substance that will dissolve in a liquid

Question 13

What is an insoluble?

Answer 13

A substance that will NOT dissolve in a solvent

Question 14

Describe simple distillation

Answer 14

1. Heat up the mixture until it evaporates
2. Pressure forces it down the condenser
3. The vapour cools and condenses into a liquid
4. It runs down the pipe and collects in the beaker