C 2.1 Calcium carbonate

Question 1

What is the chemical name and formula of limestone?

Answer 1

Calcium carbonate – CaCO₃

Question 2

What type of reaction happens when calcium carbonate is heated?

Answer 2

Thermal decomposition

Question 3

Write the word equation for the thermal decomposition of calcium carbonate.

Answer 3

Calcium carbonate → calcium oxide + carbon dioxide

Question 4

Write the symbol equation for the thermal decomposition of calcium carbonate.

Answer 4

CaCO₃ → CaO + CO₂

Question 5

What is calcium oxide also known as?

Answer 5

Quicklime

Question 6

What happens when water is added to calcium oxide?

Answer 6

It reacts to form calcium hydroxide (slaked lime)

Question 7

Write the word equation for this reaction. Carbon hydroxide

Answer 7

Calcium oxide + water → calcium hydroxide

Question 8

What is the chemical formula for calcium hydroxide?

Answer 8

Ca(OH)₂

Question 9

What is calcium hydroxide used for?

Answer 9

To neutralise acids, e.g. acidic soil or lakes

Question 10

What is limewater?

Answer 10

A solution of calcium hydroxide in water

Question 11

How is carbon dioxide tested using limewater?

Answer 11

Limewater turns milky/cloudy when carbon dioxide is bubbled through it