GCSE Chemistry: Filtering and Distilling Water

Chemistry Quiz - Purifying Water (Questions)

Clean water matters for health. This GCSE Chemistry quiz explores how drinking water is treated, how wastewater is cleaned, and how filtration, distillation and disinfection keep water safe.

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Fascinating Fact:

Disinfection kills microorganisms that can cause disease. Chlorine, ozone, or UV light may be used depending on the treatment system.

In GCSE Chemistry, purifying water means removing solids and harmful substances so it is safe to drink. You look at steps such as screening and filtration, and you compare methods like distillation and desalination, which can make pure or potable water from different sources. You also learn how wastewater is treated to reduce pollution before it is released back into the environment, and why water quality has to be carefully monitored.

Key Terms

Potable water: Water that is safe to drink because it has been cleaned and treated to remove harmful impurities.
Filtration: Separating an insoluble solid from a liquid by using a filter that lets the liquid through but traps particles.
Distillation: Purifying a liquid by boiling it and then condensing the vapour, leaving dissolved substances behind.

Frequently Asked Questions

How is drinking water purified in GCSE Chemistry?

In GCSE Chemistry, drinking water purification usually involves removing solid particles by screening and filtration, then using a final treatment step to reduce harmful microbes so the water is potable.

What is the difference between filtration and distillation?

Filtration removes insoluble solids from a liquid, but dissolved substances remain. Distillation separates a liquid from dissolved substances by evaporation and condensation, producing a purer liquid.

How is sewage treated before it goes back into rivers?

Sewage is treated by removing large solids with screens, letting grit and sludge settle, and using bacteria to break down organic waste. The cleaned water is then checked to reduce pollution.

Try These Related Quizzes

Water for drinking can come from several sources including reservoirs, rivers and boreholes. What needs to be done to water from boreholes to ensure that it is suitable for drinking?

[ ]	It needs to be filtered
[ ]	It needs to be disinfected with chlorine
[ ]	It needs to have chemicals added to it to remove impurities
[ ]	It needs to be neutralised

There are five steps in the treatment of water. What is the first step in the treatment process?

[ ]	Adding aluminium sulfate and lime to make dirt clump together, making the dirt sink
[ ]	Removing large objects
[ ]	Adding chlorine and checking the pH
[ ]	Passing it through a special filter to remove particles of grit

What is the second step?

[ ]	Adding aluminium sulfate and lime to make dirt clump together, making the dirt sink
[ ]	Removing large objects
[ ]	Adding chlorine and checking the pH
[ ]	Passing it through a special filter to remove particles of grit

The third step is...

[ ]	adding aluminium sulfate and lime to make dirt clump together, making the dirt sink
[ ]	removing large objects
[ ]	adding chlorine and checking the pH
[ ]	removing sand and soil

The next step is...

[ ]	adding aluminium sulfate and lime to make dirt clump together, making the dirt sink
[ ]	removing large objects
[ ]	adding chlorine and checking the pH
[ ]	removing sand and soil

The final step in the water treatment process is...

[ ]	adding aluminium sulfate and lime to make dirt clump together, making the dirt sink
[ ]	removing large objects
[ ]	adding chlorine and checking the pH
[ ]	removing sand and soil

Some people use filter jugs in their homes. These jugs have a top part where the water is put in and passes through the filter. Which of the following are NOT usually found in the filters in these jugs?

[ ]	Silver
[ ]	Charcoal
[ ]	Ion-exchange resin
[ ]	Chlorine

What does the carbon in the filter do?

[ ]	Removes any solid materials from the water
[ ]	Reduces the levels of chlorine, pesticides and other organic impurities in the water
[ ]	Discourages the growth of bacteria within the filter
[ ]	Removes calcium, magnesium, lead, copper and aluminium ions from the water

The water passed through the treatment process is not pure water. How can we produce pure water?

[ ]	Filter it again
[ ]	Distil it
[ ]	Disinfect it again
[ ]	Remove any solid materials

10.

De-ionising is an alternative method to produce pure water. How does it work?

[ ]	It removes all ions except H⁺ and OH^- ions
[ ]	It removes all ions except Ca²⁺ and OH^- ions
[ ]	It removes all ions except H⁺ and Mg²⁺ ions
[ ]	It adds Mg²⁺ ions and H⁺ ions

You can find more about this topic by visiting BBC Bitesize - Water

Chemistry Quiz - Purifying Water (Answers)

Water for drinking can come from several sources including reservoirs, rivers and boreholes. What needs to be done to water from boreholes to ensure that it is suitable for drinking?

[ ]	It needs to be filtered
[x]	It needs to be disinfected with chlorine
[ ]	It needs to have chemicals added to it to remove impurities
[ ]	It needs to be neutralised

Usually water from boreholes is fairly clean as it has been filtered by the rocks around the borehole

There are five steps in the treatment of water. What is the first step in the treatment process?

[ ]	Adding aluminium sulfate and lime to make dirt clump together, making the dirt sink
[x]	Removing large objects
[ ]	Adding chlorine and checking the pH
[ ]	Passing it through a special filter to remove particles of grit

This is done by passing the water through a screen made of bars of metal

What is the second step?

[ ]	Adding aluminium sulfate and lime to make dirt clump together, making the dirt sink
[ ]	Removing large objects
[ ]	Adding chlorine and checking the pH
[x]	Passing it through a special filter to remove particles of grit

The water is passed through a filter made of fine sand

The third step is...

[ ]	adding aluminium sulfate and lime to make dirt clump together, making the dirt sink
[ ]	removing large objects
[ ]	adding chlorine and checking the pH
[x]	removing sand and soil

This is done in a sediment tank

The next step is...

[x]	adding aluminium sulfate and lime to make dirt clump together, making the dirt sink
[ ]	removing large objects
[ ]	adding chlorine and checking the pH
[ ]	removing sand and soil

The dirt that collects is collected from the bottom of the settling tank and taken to landfill sites

The final step in the water treatment process is...

[ ]	adding aluminium sulfate and lime to make dirt clump together, making the dirt sink
[ ]	removing large objects
[x]	adding chlorine and checking the pH
[ ]	removing sand and soil

The chlorine kills any bacteria and other microbes that are in the water and the pH is checked to ensure that the water is neither too acidic nor too alkaline

[ ]	Silver
[ ]	Charcoal
[ ]	Ion-exchange resin
[x]	Chlorine

Charcoal is made from carbon

What does the carbon in the filter do?

[ ]	Removes any solid materials from the water
[x]	Reduces the levels of chlorine, pesticides and other organic impurities in the water
[ ]	Discourages the growth of bacteria within the filter
[ ]	Removes calcium, magnesium, lead, copper and aluminium ions from the water

These are not removed at the water purification plant