Water

Question 1

Desalination

Answer 1

A process where fresh water is obtained from sea water

Evaporation followed by condensation or reverse osmosis

Question 2

5 Stages of Water Treatment

Answer 2

Screening: water passed through wire mesh or scree to remove floating material
Settling: water flows in large tanks and aluminium sulphate is added
Filtration: water is passes through beds of sand
Chlorination: chlorine is added to kill bacteria
Fluoridation: fluoride is added to prevent tooth decay

Question 3

Soft water

Answer 3

Lathers with soap

Question 4

Advantages and disadvantages of hard water

Answer 4

Advantages
•bones and teeth
•brewing and tanning

Disadvantages:
•wastes soap
•creates limescale

Question 5

Brine

Answer 5

Salt and water

Question 6

Reverse Osmosis

Answer 6

The modern way of removing salt from sea water, involves filtering water under high pressure.

Question 7

Temporary hardness

Answer 7

Hardness that can be removed by boiling

Question 8

Permanent hardness

Answer 8

Hardness that can’t be removed by boiling

Question 9

Shapes of meniscus’

Answer 9

Concave and convex