End Of Unit Questions

Question 1

Name the 4 substances used to create concrete

Answer 1

• sand
• water
• aggregate
• cement

Question 2

Name the products formed when calcium carbonate is heated strongly

Answer 2

• calcium oxide

* carbon dioxide

Question 3

Write a word equation for the reaction of calcium oxide with water

Answer 3

Calcium oxide + water –> calcium hydroxide

Question 4

Limewater goes cloudy when mixed with carbon dioxide, explain why using an equation in your answer

Answer 4

Calcium carbonate is formed and is insoluble

Calcium hydroxide + carbon dioxide –> calcium carbonate + water

Question 5

Explain as fully as you can why acids damage limestone

Answer 5

Acids react with calcium carbonate producing carbon dioxide and a salt, the salt dissolves in water so the amount of limestone decreases

Question 6

Farmers spread calcium hydroxide on fields with acidic soils, explain why, naming the type of reaction that takes place and the property of calcium hydroxide on which this reaction takes place

Answer 6

Calcium hydroxide reacts with acids because it is an alkali so the reaction is neutralisation

Question 7

Balance this symbol equation:

K2CO3 + HCl –> KCl + H2O + CO2

Answer 7

K2CO3 + 2HCl –> 2KCl + H2O + CO2

Question 8

How is cement made?

Answer 8

Mix limestone and clay in a lime kiln at very hot temps and then grind into a powder