Chemical Changes

Question 1

What is a chemical reaction?

Answer 1

When the substance becomes something else and can not be reversed

Question 2

What are signs that a chemical reaction has occurred

Answer 2

Change in temperature
Formation of a precipitate
Change in colour

Question 3

What reaction re-arranges atoms?

Answer 3

Chemical reactions

Question 4

Do chemical reactions always make a new substance?

Answer 4

Yes

Question 5

Are physical changes reversible

Answer 5

Yes

Question 6

Do chemical reactions involve energy transfers

Answer 6

Yes

Question 7

Give an example of a chemical reaction

Answer 7

Baking raw cake to cooked cake

Question 8

Give an example of a physical change

Answer 8

Boiling water to make steam

Question 9

What does a fuel need to burn?

Answer 9

Oxygen and heat

Question 10

What does combustion mean?

Answer 10

Burning

Question 11

What’s the word equation for burning

Answer 11

Fuel+ Oxygen —-> carbon dioxide + water (vapour)

Question 12

What reaction is burning something?

Answer 12

Oxidation reaction

Question 13

What is thermal decomposition?

Answer 13

Breaking a substance down, using heat, into 2 or more products

Question 14

What’s the most reactive Carbonate?

Answer 14

Calcium carbonate

Question 15

What’s the least reactive carbonate

Answer 15

Copper carbonate

Question 16

What is endothermic

Answer 16

Heat energy is taken in from surroundings TEMPERATURE FALLS

Question 17

What is exothermic?

Answer 17

When heat energy is given out to the surroundings TEMPERATURE RISES

Question 18

What is a physical reaction?

Answer 18

A substance that changes state but doesn’t become anything else