Potable water

Bacteria can cause disease.

Bacterial cells do not have a nucleus.

Which term describes bacterial cells?

Tick (✓) one box.

Eukaryotic

Fungal

Prokaryotic

Bacterial cells have no nucleus and are smaller than animal cells.

Give one other difference between bacterial cells and animal cells.

Escherichia coli (E. coli) is a type of bacterium.

E. coli causes symptoms of food poisoning.

Water companies sterilise rain water to produce drinking water.

The drinking water is then transported to homes in underground pipes.

Flooding can cause contamination of the drinking water by E. coli.

Suggest how people should treat drinking water at home if there is a risk of E. coli contamination.

Figure 11 shows two graphs:

The rainfall in one town in one month.

The number of cases of E. coli in the town in the same month.

The rainfall on day 12 was greater than on day 10.

Calculate how many times greater.

Symptoms of E. coli infection usually occur 5 days after infection.

A scientist stated:

‘Increased rainfall causes an increase in the number of cases of E. coli.’

Describe one piece of evidence from Figure 11 that supports the scientist’s statement.

Why might the number of cases of E. coli infection increase in the future?

Tick (✓) one box.

Climate change is causing loss of habitats for wildlife.

Climate change is causing more extreme rainfall.

Climate change is causing sea-levels to be lower.

Climate change is caused by an increase in the concentration of greenhouse gases in the atmosphere.

Carbon dioxide is a greenhouse gas.

Name two other greenhouse gases.

Do not refer to carbon dioxide in your answer.

Describe one way the rate of increase in carbon dioxide concentration in the atmosphere could be reduced.

Bacteria can cause disease.

Bacterial cells do not have a nucleus.

Which term describes bacterial cells?

Tick (✓) one box.

Eukaryotic

Fungal

Prokaryotic

Bacterial cells have no nucleus and are smaller than animal cells.

Give one other difference between bacterial cells and animal cells.

Escherichia coli (E. coli) is a type of bacterium.

E. coli causes symptoms of food poisoning.

Water companies sterilise rain water to produce drinking water.

The drinking water is then transported to homes in underground pipes.

Flooding can cause contamination of the drinking water by E. coli.

Suggest how people should treat drinking water at home if there is a risk of E. coli contamination.

Figure 1 shows two graphs:

The rainfall in one town in one month.

The number of cases of E. coli in the town in the same month.

The rainfall on day 12 was greater than on day 10.

Calculate how many times greater.

Symptoms of E. coli infection usually occur 5 days after infection.

A scientist stated:

‘Increased rainfall causes an increase in the number of cases of E. coli.’

Describe one piece of evidence from Figure 1 that supports the scientist’s statement.

Why might the number of cases of E. coli infection increase in the future?

Tick (✓) one box.

Climate change is causing loss of habitats for wildlife.

Climate change is causing more extreme rainfall.

Climate change is causing sea-levels to be lower.

Climate change is caused by an increase in the concentration of greenhouse gases in the atmosphere.

Carbon dioxide is a greenhouse gas.

Name two other greenhouse gases.

Do not refer to carbon dioxide in your answer.

Describe one way the rate of increase in carbon dioxide concentration in the atmosphere could be reduced.

Figure 1 shows part of the water cycle.

Name processes A, B and C.

Choose answers from the box.

Drinking water can be produced from sea water.

Which process is used to produce drinking water from sea water?

Tick (✓) one box.

Desalination

Digestion

Screening

Why is producing drinking water from sea water expensive?

Tick (✓) one box.

The process requires energy.

The sea water must be filtered.

The sea water temperature is too high.

Which two processes are used to kill bacteria during the production of drinking water?

Tick (✓) two boxes.

Adding chlorine

Exposure to ultraviolet light

Freezing

Grit removal

Sedimentation

Why is it important to kill bacteria in water during the production of drinking water?

Figure 4 shows part of the water cycle.

Name processes A and B shown on Figure 4.

Water that is safe to drink is called potable water.

Give two methods used to sterilise potable water.

Explain why it is more expensive to produce potable water from sea water than from river water.

Waste water must be treated to produce potable water.

Waste water from fields where crops are growing may contain chemicals.

Suggest two types of chemical from fields where crops are growing that must be removed from waste water.

Water can be sterilised.

Sterilised water is safe to drink.

Which two methods are used to sterilise water?

Tick (✓) two boxes.

Removing grit

Removing sediment

Using carbon dioxide

Using chlorine

Using ozone

Why is sterilised water safer to drink than water that has not been sterilised?

Salt can be separated from sea water.

Which method uses membranes and energy to separate salt from sea water?

Tick (✓) one box.

Digestion

Paper chromatography

Reverse osmosis

Screening

A student distilled sea water to obtain pure water.

Figure 6 shows some of the equipment used.

Describe what happens during distillation.

The student only obtained 10 cm³ of pure water from 50 cm³ of sea water.

How could the student improve the method to obtain more pure water from 50 cm³ of sea water?

A water purification system produced 28 125 dm³ of water.

This system cost £4500.

Calculate the cost per dm³ of water.

Cost = £ per dm³ __________________

A different system uses solar panels to extract water vapour from the air to produce liquid water.

The solar panel system produces 6 dm³ of water each day.

Calculate the volume of water this system would produce in 15 years.

1 year = 365 days

Volume of water produced = dm³ __________________

Suggest one reason why the solar panel system is not widely used in the UK.

Figure 12 shows some of the processes in the water cycle.

Name process A and process B.

shows the locations of fresh water on Earth.

Calculate the amount of fresh water in lakes as a percentage of the total amount of fresh water.

Give two ways humans pollute the water in lakes.

Do not refer to litter, plastic pollution or rubbish.

The surface of a lake can freeze if the water at the surface of the lake cools to 0 °C.

Figure 14 shows the temperature of the water at increasing depth in a lake in winter.

Suggest why organisms in the lake can survive in winter.

Use Figure 14.

The middle layer of water is from 7 metres below the surface to 15 metres below the surface.

The temperature at a depth of 7 metres below the surface is 0 °C.

Determine the change in temperature per metre in the middle layer of water.

Use the equation:

Write down the equation which links density (ρ), mass (m) and volume (V).

The density of ice is 920 kg/m³.

Calculate the volume of 2.3 kg of ice.

Volume = m³ __________________

Describe a method to measure the mass and volume of a liquid.

Water that is safe to drink is called potable water.

Why is some potable water not pure water?

Explain how potable water is obtained from sea water by distillation.

Potable water can be obtained from sea water using reverse osmosis.

Describe the function of the membrane in reverse osmosis.

Give one reason why the process of reverse osmosis is expensive.

Do not refer to the cost of the membrane.

A new method involving solar panels can be used to obtain potable water.

Table 1 compares the costs involved with the solar panel method and the reverse osmosis method.

Calculate the time in years until the solar panel method becomes as cost effective as reverse osmosis.

Water is cycled through the environment.

Rain provides fresh water.

Fresh water in the ground contains small amounts of dissolved substances.

Suggest one source of these dissolved substances.

Figure 5 shows the total monthly rainfall from November 2017 to October 2018 in the UK.

Give two conclusions you can make from the data shown in Figure 5.

Determine the percentage increase in rainfall in the month of January 2018 compared to the month of November 2017.

Suggest one reason why scientists cannot accurately predict the total rainfall in the UK for November 2020.

A student produced distilled water from fresh water.

Figure 6 shows the apparatus used.

The student stated that the thermometer measured the boiling point of water.

The reading on the thermometer was 102 ºC

Describe how the apparatus can be changed to obtain the correct value for the boiling point of water.

Give one reason why the change is needed to obtain the correct value.

The student collected less distilled water than expected from a sample of fresh water.

Suggest one change to the apparatus to increase the volume of distilled water collected from the fresh water sample.

Give one reason why this suggestion would increase the volume of distilled water collected.

Sea water in some parts of the world is used to produce potable water.

Distillation can be used to desalinate sea water.

Explain one disadvantage of using distillation to obtain potable water.

Name one other method used for desalination.

Do not refer to distillation in your answer.