Fichas
Purifying and Testing Water
Fichas del conjunto (25)
- 1What are the four main sources of water?Rivers.
Lakes.
Reservoirs.
Aquifiers (wells and bore holes). - 2What is water an important resource for?Industry as well as being essential for drinking, washing and other jobs in the home.
- 3What does the chemical industry use large amounts of water for?For cooling.
As a solvent.
As a cheap raw material. - 4Why is it important not to waste water?Because in some places the demand for water is higher than the supply.
- 5Why is water treated?To purify it and make sure it is safe to drink before it reaches homes or factories.
- 6What can untreated (raw) water contain?Insoluble particles.
Pollutants.
Microbes.
Dissolved salts and minerals. - 7What are the three processes of water treatment?Sedimentation.
Filtration.
Chlorination. - 8What happens in the sedimentation process?The water settles to allow the insoluble particles to sink.
- 9What happens in the process of filtration?It is to remove the very fine particles.
- 10What happens in the process of chlorination?It is to kill the microorganisms in the water.
- 11Why is tap water not pure?Because it contains soluble materials that are not removed in the normal water treatment process. There is the possibility that some of the materials may be poisonous and, in that case, extra steps must be taken to remove them.
- 12What can you do to water to make sure it is absolutely pure?It must be distilled. This uses lots of energy, so it is very costly.
- 13Why is making drinking water from sea water extremely expensive?Huge amounts of expensive energy would be needed in order to distil sea water.
Sea water is corrosive, so the equipment needed would be very costly.
These factors means we are prevented from doing it because the cost is too high. - 14What are the pollutants that may be found in water supplies?They include:
Nitrates from the run-off of fertilisers.
Lead compounds from old pipes in the plumbing.
Pesticides from spraying crops near to the water supply.
(These materials are more difficult to remove from the water). - 15Why are the dissolved ions of some salts easy to identify?They will undergo precipitation reactions.
- 16When does a precipitation reaction occur?When an insoluble solid is made from mixing two solution together.
- 17How can sulfates be detected and why?By using barium chlorides solution: a white precipitate of barium sulfate forms.
- 18What is the symbol and word equation for the reaction between sodium sulfate and barium chloride?Sodium sulfate + Barium chloride = Barium sulfate (white) + sodium chloride
Na2SO4 + BaCl2 = BaSO4 + 2NaCl - 19What is silver nitrate solution used to detect?Used to detect halide ions.
- 20With silver nitrates what coloured precipitate do chlorides form?White precipitate.
- 21With silver nitrates what coloured precipitate do bromides form?Cream precipitate.
- 22With silver nitrates what coloured precipitate do iodides form?Pale yellow precipitate.
- 23What is the symbol and word equation for the reaction between sodium chloride and silver nitrate?Sodium chloride + silver nitrate = silver chloride (white) +sodium nitrate
NaCl + AgNO3 = AgCl + NaNO3 - 24What is the symbol and word equation for the reaction between Sodium bromide and silver nitrate?Sodium bromide + silver nitrate = Silver bromide (cream) + Sodium nitrate
NaBr + AgNO3 = AgBr + NaNO3 - 25What is the symbol and word equation for the reaction between Sodium iodide and silver nitrate?Sodium iodide + silver nitrate = silver iodide (pale yellow) + sodium nitrate
NaI + AgNO3 = AgI + NaNO3
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- Descripción
- GCSE (C4) chemistry Fichas sobre Purifying and Testing Water, creado por Rebecca Smith el 13/04/2017.
- Creado por
- Rebecca Smith · abr 2017
- Actualizado
- 7 mar 2018
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