Reactions of calcium compounds

Question 1

What is limewater used to test for?

Answer 1

Carbon dioxide

Question 2

What is the test for carbon dioxide and how do you know if it is present?

Answer 2

You bubble carbon dioxide through limewater and if it turns cloudy/ milky in colour it means that insoluble calcium carbonate has been created therefore carbon dioxide is present.

Question 3

When water is added to calcium oxide what is released?

Answer 3

Heat

Question 4

What is created if you add water to calcium oxide?

Answer 4

Calcium hydroxide

Question 5

What is created if you add lots of water to calcium hydroxide?

Answer 5

Limewater

Question 6

Complete the word equation:

Calcium carbonate —-(heat)—> ________________

Answer 6

calcium oxide + carbon dioxide

Question 7

Complete the word equation:

calcium oxide + water ———-> _____________

Answer 7

calcium hydroxide

Question 8

complete the word equation:

calcium hydroxide + carbon dioxide ———–>_________

Answer 8

Calcium carbonate

Question 9

Calcium carbonate, calcium oxide and calcium hydroxide can all be used to _________ acidic compounds.

Answer 9

Neutralise

Question 10

What do some farmers use calcium compounds for?

Answer 10

To neutralise acid soil so that their crops will grow better

Question 11

Explain why the gases emitted by coal-fired power stations need to be cleaned up, and how calcium carbonate can be used to do this.

Answer 11

The waste gases from coal-fired power station contain sulphur dioxide and nitrogen oxides, which are acidic gases. These gases douse acid rain if they get into the atmosphere.

Wet, powdered calcium carbonate is sprayed into the waste gases to neutralise them.