Unit 1

Question 1

4 chemical reactions that happen around you

Answer 1

Baking a cake
Plant growing
Making toast
Burning petrol

Question 2

Indicate a chemical reaction has taken place

Answer 2

Colour change
Temperature
Effervescent
Precipitation

Question 3

Exothermic and endothermic

Answer 3

An exothermic reaction gives out heat which mean the temperature increases
An endothermic takes in heat which means the temperature decreases

Question 4

Example of exothermic and endothermic

Answer 4

Burning gas in a cooker

Single use ice pack

Question 5

Chemical reactions and physical reactions

Answer 5

A chemical reaction is when a new substance is formed and it isn’t easy to reverse

A physical reaction is when no new substances is made and it’s easy to reverse

Question 6

Examples of physical and chemical reactions

Answer 6

Ironing clothes Chemical: baking a cake
Frying an egg
Apples rotting
Melting ice cubes
Boiling water

Question 7

Describe blah blah

Answer 7

Precipitation: solid forming
Effervescence: bubbles
Exothermic heat given off
Endothermic heat taken in

Question 8

Ph ranges

Answer 8

Acid - 1-6
Alkali- 8-14
Neautral- 7

Question 9

Acid alkali substances

Answer 9

Acid- lemon juice and vinegar

Alkali- toothpaste and baking soda

Question 10

Acid rain

Answer 10

Acid rain is formed from factories and vehicles polluting the air. The carbon dioxide dissolves with the rain turning it acidic which forms acid rain