Water

Question 1

Blue cobalt paper

Answer 1

Used to test for water. It is blue when dry - water turns it pink.

Question 2

The freezing point of

Answer 2

Pure water is 0 degrees C. It’s boiling point is 100 degrees C.

Question 3

Ice is less dense than water

Answer 3

Therefore it floats on water

Question 4

Water is an excellent solvent

Answer 4

Many substances dissolve in it

Question 5

The water cycle

Answer 5

How water is recycled on the planet

Question 6

Screening

Answer 6

Wire mesh

Question 7

Settling

Answer 7

Settling tanks

Question 8

Filtration

Answer 8

Sand and gravel filter beds

Question 9

Chlorination

Answer 9

Adding chlorine to kill bacteria

Question 10

Fluoridation

Answer 10

Fluoride for teeth

Question 11

Hard water

Answer 11

Water that does not easily form a lather with soap

Question 12

Soft water

Answer 12

Water that forms a lather easily with soap

Question 13

Hardness in water is caused by

Answer 13

The presence of calcium ions dissolved in the water.

Question 14

Hardness can be removed by

Answer 14

Passing the water through an ion exchange resin or by distillation

Question 15

Ion exchange resin

Answer 15

Exchanges calcium ions for hydrogen ions to remove hardness

Question 16

Electrolysis

Answer 16

The production of a chemical reaction by using electricity

Question 17

Hoffman voltameter

Answer 17

Used in the electrolysis of water to form H2 and 02. Twice as much hydrogen as oxygen is formed because water is H2O