Purifying And Testing Water

Question 1

Explain why water is an important resources for many important industrial chemical processes

Answer 1

Because the industry uses large amounts of water for cooling, as a solvent and as a cheap raw material

Question 2

List some of the pollutants that may be found in domestic water supplies

Answer 2

Nitrate residues
Lead compounds
Pesticide residues

Question 3

List the type of substances present in water before it is purified

Answer 3

Dissolved salts and minerals
Microbes
Pollutants
Insoluble materials

Question 4

What is the purpose of chlorination?

Answer 4

Kills microbes in water

Question 5

Recall that barium chloride solution is used to test dir sulfate ions

Answer 5

Gives a white precipitate

Question 6

Recall that silver nitrate solution is used to test for halide ions

Answer 6

Chloride ions gives a white precipitate
Bromide ions give a cream precipitate
Iodide ions give a pale yellow precipitate

Question 7

Explain why drinking water may contain some of the pollutants nelow:

• Nitrate
• lead compounds
• pesticide

Answer 7

• nitrates - from the run-off of fertilisers
• lead compounds- from old pipes in plumbing
• pesticides - from spraying crops near to the water supply

Question 8

Describe the water purification process

Answer 8

• Sedimentation - the water settles to allow the insoluble particles to sink
• filtration - to remove very fine particles
• chlorination - to kill the microorganisms in water

Question 9

Word equation for sodium sulfate and barium chloride

Answer 9

Sodium sulfate + barium chloride ->sodium chloride + barium sulfate

Question 10

Word equation for sodium chloride and silver nitrate

Answer 10

Sodium chloride + silver nitrate -> silver chloride + sodium nitrate

Question 11

Word equation for sodium bromide and silver nitrate

Answer 11

Sodium bromide + silver nitrate -> silver bromide + sodium nitrate

Question 12

Word equation for sodium iodide and silver nitrate

Answer 12

Sodium iodide + silver nitrate -> silver iodide + sodium nitrate

Question 13

Explain the disadvantages of using distillation of sea water to make large quantities of fresh water

Answer 13

Lost of energy so is costly

Expensive equipment

Question 14

Recall different types of water resources found in the united kingdom

Answer 14

Lakes
Rivers
Aquifers
Reservoirs

Question 15

Why aren’t all soluble substances are removed?

Answer 15

They are not a danger and may improve the taste of the water