Water quality

Question 1

What does drinking water need to be?

Answer 1

Good quality.

Question 2

What is water essential for?

Answer 2

Life.

Question 3

What must water be free f?

Answer 3

• Poisonous salts (e.g.phosphates and nitrates).

- Harmful microbes.

Question 4

Why does water need to be free of harmful microbes?

Answer 4

As microbes in water can cause diseases such as cholera and dysentery.

Question 5

Where does most of our drinking water come from?

Answer 5

Reservoirs.

Question 6

How does water get into reservoirs?

Answer 6

It flows from rivers and groundwater.

Question 7

What do watercompanies choose to do?

Answer 7

Build reservoirs where theree’s a good supply of clean water.

Question 8

What do government agencies do?

Answer 8

Keep a close eye on pollution in reservoirs, rivers and groundwater.

Question 9

How do we make water of a good quality?

Answer 9

Water from reservoirs goes to the water treatment works for treatment.

Question 10

How do the water treatment works work?

Answer 10

• The water passes through a mesh screen to remove big bits like twigs.
• Chemicals are added to make solids and microbes stuck together and fall to the bottom.
• The water is filtered through gravel beds to remove all the solids.
• Water is chlorinated to kill off any harmful microbes left.

Question 11

What are some people not with the water treatment process.

Answer 11

Not satisfied.

Question 12

What do the people who are unsatisfied about the water treatment process do?

Answer 12

They buy filters that contain carbon or silver to remove substances from their tap water.

Question 13

What do the filters do that are bought by people who are unsatisfied with the water treatment process?

Answer 13

• The carbon in the filters removes chlorine taste.

- The silver in the filters is supposed to kill bugs.

Question 14

What do people in hard water areas buy?

Answer 14

Water softeners which contain ion exchange resins.

Question 15

What is totally pure water?

Answer 15

Water with nothing dissolved in it.

Question 16

How can totally pure water be produced?

Answer 16

By distillation.

Question 17

How do we produce totally pure water through distillation?

Answer 17

• By boiling water to make steam.

- Then condensing the steam.

Question 18

Why don’t we use the distilling process to produce totally pure water in tap water?

Answer 18

Because this process is too expensive, because lots of energy would be needed to boil all he water we use.

Question 19

Where is distilled water used in?

Answer 19

Chemistry labs.

Question 20

What is added to drinking water?

Answer 20

• Fluoride (in some parts of the country).

- Chloride.

Question 21

Why is fluoride added to drinking water?

Answer 21

Because it helps to reduce tooth decay.

Question 22

Why is chlorine added to drinking water?

Answer 22

To prevent disease.

Question 23

What does adding fluoride and chlorine to water have?

Answer 23

Disadvantages as well as advantages.

Question 24

What are the disadvantages of adding chlorine to drinking water?

Answer 24

• Some studies have linked this with an increase in certain cancers.
• It can react with other natural substances in water to produce toxic by-products, which some people think could cause cancer.

Question 25

What are the disadvantages of adding fluoride to drinking water?

Answer 25

• High doses can cause cancer and bone problems.
• There are concerns about whether it is right to mass medicate, meaning people can’t choose whether their tap water has added fluoride.

Question 26

What is monitored in drinking water?

Answer 26

The levels of chemicals added.