Air and water

The Earth surface is covered with _____ % of water.

• 60%

• 70%

• 80%

• 90%

Your bones contain _____% of water.

• 62%

• 82%

• 72%

• 82%

Your kidneys contain about _____% of water.

• 72%

• 82%

• 42%

• 62%

Your blood contains ______% of water.

• 70

• 80

• 90

• 60

To test the presence of water in an unknown liquid, anhydrous copper (II) sulfate is added. If this changes from white to ______, then the liquid contains water.

• pink

• purple

• black

• blue

Another way to test the presence of water is when a blue cobalt chloride paper is dip into the liquid, the paper turns ________.

• red

• pink

• orange

• blue

Impure water is passed through screens to filter out floating ________.

• debris

• boat

• paper

• leaves

A process wherein coarse sand traps larger, insoluble particles. The sand also contains specially grown microbes which remove some of the bacteria.

• chlorination

• sedimentation

• coagulation

• filtration

A ________ tank has chemicals added to it to make the smaller particles stick together and sink to the bottom of the tank.

• flocculation

• coagulation

• sedimentation

• filtration

A little amount of this gas is added to the water which sterilizes and kills the remaining bacteria.

• coagulants

• chlorine

• ozone

• carbon dioxide