AQA GCSE COMBINED SCIENCE TRILOGY
HIGHER TIER CHEMISTRY PAPER 2H 6
◉ Potable water is not pure. Pure water only contain. Answer: H2O
molocules.
◉ Potable may contain. Answer: a lot of dissolved substances.
◉ The pH of potable water is. Answer: between 6.5 and 8.5
◉ When it rains water can be collect as. Answer: surface water (in
lakes, rivers and reservoirs)
or as groundwater (in rocks called aquifers)
◉ What are the two proccesses to treat water?d. Answer: Filtration -
A wire mesh screens out large twigs and then gravel and sand beds
filter out any other solid bits.
Sterilisation - It's sterilised to kill any harmful bacteria or microbes.
This is done by bubbling chlorine gas through it or using ozone or
ultraviolet light.
,◉ Sterilisation. Answer: It's sterilised to kill any harmful bacteria or
microbes. This is done by bubbling chlorine gas through it or using
ozone or ultraviolet light.
◉ Filtration. Answer: A wire mesh screens out large twigs and then
gravel and sand beds filter out any other solid bits.
◉ In very dry countries, seawater must be treated by. Answer:
desalination.
◉ Steps of distillation:. Answer: Stage 1 - Test the pH using a pH
meter. If it's too high or too low neutralise it.
Stage 2 - Set up equipment.
Stage 3 - The liquid will boil to become a gas.
Stage 4 - The cold water around the condenser will make the steam
condense back into liquid water.
Stage 5 - Collect the water.
Stage 6 - Retest the pH and see if it's neutral.
, ◉ After distillation, how could you tell if salts were presents?.
Answer: Crystals would be formed in the bottomed flask.
◉ How else might seawater be treated?. Answer: Reverse osmosis.
◉ What does reverse osmosis involve?. Answer: The salt water is
passed through a membrane that only wallows water molecules to
pass through. Ions and larger molecules are trapped by the
membrane.
◉ Why is reverse osmosis and distillation not practical for
producing large quantities of water?. Answer: It required loads of
energy and therefore is expensive.
◉ Sewage from domestic or agricultural sources has to be. Answer:
treated to remove any organic matter and harmful microbes before
it can be put back into freshwater. This is to stop pollution and heath
risks.
◉ The water may also contain. Answer: harmful chenicals.
◉ Sewage treatment stages:. Answer: Stage 1: Before being treated
the sewage is screened (large bits are removed)
HIGHER TIER CHEMISTRY PAPER 2H 6
◉ Potable water is not pure. Pure water only contain. Answer: H2O
molocules.
◉ Potable may contain. Answer: a lot of dissolved substances.
◉ The pH of potable water is. Answer: between 6.5 and 8.5
◉ When it rains water can be collect as. Answer: surface water (in
lakes, rivers and reservoirs)
or as groundwater (in rocks called aquifers)
◉ What are the two proccesses to treat water?d. Answer: Filtration -
A wire mesh screens out large twigs and then gravel and sand beds
filter out any other solid bits.
Sterilisation - It's sterilised to kill any harmful bacteria or microbes.
This is done by bubbling chlorine gas through it or using ozone or
ultraviolet light.
,◉ Sterilisation. Answer: It's sterilised to kill any harmful bacteria or
microbes. This is done by bubbling chlorine gas through it or using
ozone or ultraviolet light.
◉ Filtration. Answer: A wire mesh screens out large twigs and then
gravel and sand beds filter out any other solid bits.
◉ In very dry countries, seawater must be treated by. Answer:
desalination.
◉ Steps of distillation:. Answer: Stage 1 - Test the pH using a pH
meter. If it's too high or too low neutralise it.
Stage 2 - Set up equipment.
Stage 3 - The liquid will boil to become a gas.
Stage 4 - The cold water around the condenser will make the steam
condense back into liquid water.
Stage 5 - Collect the water.
Stage 6 - Retest the pH and see if it's neutral.
, ◉ After distillation, how could you tell if salts were presents?.
Answer: Crystals would be formed in the bottomed flask.
◉ How else might seawater be treated?. Answer: Reverse osmosis.
◉ What does reverse osmosis involve?. Answer: The salt water is
passed through a membrane that only wallows water molecules to
pass through. Ions and larger molecules are trapped by the
membrane.
◉ Why is reverse osmosis and distillation not practical for
producing large quantities of water?. Answer: It required loads of
energy and therefore is expensive.
◉ Sewage from domestic or agricultural sources has to be. Answer:
treated to remove any organic matter and harmful microbes before
it can be put back into freshwater. This is to stop pollution and heath
risks.
◉ The water may also contain. Answer: harmful chenicals.
◉ Sewage treatment stages:. Answer: Stage 1: Before being treated
the sewage is screened (large bits are removed)
