When limestone is heated it forms lime (calcium oxide) and carbon dioxide.

CaCO3(s) → CaO(s) + CO2(g)

Which statement is NOT correct?

• Carbon dioxide is a greenhouse gas which may contribute to climate change.

• Slaked lime is used to neutralise industrial waste.

• The lime can be used to treat alkaline soil.

• This reaction is an example of thermal decomposition.

Lime (calcium oxide) is used to treat waste water from a factory. Which substance is removed by the lime?

• ammonia

• sodium chloride

• sodium hydroxide

• sulfuric acid

Which process is used to make lime (calcium oxide) from limestone (calcium carbonate)?

• chromatography

• electrolysis

• C fractional distillation

• thermal decomposition

When compound X is heated, it changes colour from green to black. Compound Y is formed and a gas is given off which turns limewater milky.

X and Y are ......................................, respectively.

• calcium carbonate and calcium oxide

• copper carbonate and carbon

• copper carbonate and copper oxide

• copper sulfate and copper oxide

In which process is carbon dioxide not formed?

• burning of natural gas

• fermentation

• heating lime

• respiration

Carbon dioxide is produced when dilute hydrochloric acid reacts with

• calcium sulfate.

• carbon.

• copper(II) carbonate.

• limewater.

Two industrial processes that involve heating are

1. extracting iron from its ore using a blast furnace

2. making lime.

In which of these processes is calcium carbonate used?

• Process 1

• Process 2

• Both 2 processes

• None of the processes

Limestone can be used to

• make lime

• make cement

• mix with hematite to blast furnace

• neutralise acidic soil

Subsatnce is used to treat industrial waste.

What is X and which type of reaction occur during the treatment?

• Calcium oxide (lime), neutralisation reaction

• Calcium oxide (lime), redox reaction

• carbon, neutralisation reaction

• carbon, redox reaction

The diagram shows the soil pH range over which a vegetable grows well.

The pH of the soil to be used is 5.5.

Why is lime added to the soil before planting the vegetable?

• The lime acts as a catalyst.

• The lime changes the soil acidity.

• The lime is an indicator.

• The lime supplies nitrogen.