Water：練習題

Which substance is used in a chemical test to show the presence of water?

In the treatment of domestic water, what is the purpose of filtration?

The table identifies some substances found in natural water and their potential effects. Which row is correct?

Natural water sources can contain various substances. Why are some metal compounds considered potentially harmful to humans?

Which substance found in natural water sources is beneficial to aquatic life?

Describe the color change observed when water is added to a sample of anhydrous copper(II) sulfate.

What is the specific purpose of the chlorination step in the treatment of the domestic water supply?

Identify and distinguish between the two physical processes used to remove insoluble solids during domestic water treatment.

A student is given a colorless liquid and asked to perform chemical tests to confirm if it is water and if it is pure water.
(a) Describe a chemical test using anhydrous copper(II) sulfate to show the presence of water, including the observation for a positive result.
(b) Describe how the student can use the boiling point of the liquid to determine if the water is pure.

The domestic water supply undergoes several stages of treatment before it is safe for human consumption.
(a) Explain the purpose of sedimentation and filtration in the treatment process.
(b) Why is chlorine added to the water at the end of the treatment?
(c) What is the purpose of using carbon (charcoal) during water treatment?