Water

Question 0

Water is known as the ….. solvent

Answer 0

Universal

Question 1

What does the water cycle mean?

Answer 1

That the water is endlessly recycled

Question 2

Water dissolves most…compounds

Answer 2

Ionic

Question 3

How does water dissolve ionic compounds?

Answer 3

Water molecules surround the ions and disrupt the ionic bonding, so the solid structure of the ionic compound gradually falls apart.

Question 4

Water molecules are polar because…

Answer 4

They have a positive hydrogen side and a negative oxygen side

Question 5

The slightly negative side of the water molecule attracts the …. ions and the slightly positive side attracts the …. ions

Answer 5

Positive

Negative

Question 6

What is the basic water treatment layout?

Answer 6

Reservoir > screening > ozone treatment > removal of solids and microbes > filtration > pH correction > chlorination > storage > homes

Question 7

What does water pass through to remove big bits such as twigs and leaves?

Answer 7

A mesh screen

Question 8

Hard water makes ….

Clue: they both begin with s

Answer 8

Scum and scale

Question 9

Hard water won’t easily form a …

Answer 9

Lather

Question 10

Hard water forms ….. on the insides of pipes, boilers and kettles

Answer 10

Scale (mostly calcium carbonate)

Question 11

Why is a kettle with scale less efficient than one without?

Answer 11

Because scale acts as a thermal insulator, so a kettle with scale on the heating element will take longer to boil

Question 12

Hardness is caused by…

Answer 12

Ca2+ and Mg2+ ions ( calcium and magnesium ions)

Question 13

Why do you get hard water in certain areas?

Answer 13

Because of the rock types. Hardness often comes from limestone, chalk and gypsum

Question 14

What are calcium ions good for?

Answer 14

Teeth and bones

Question 15

Why can scale inside your pipes be a good thing?

Answer 15

Because it forms a protective coating and stops poisonous metal ions from getting into drinking water. It also protects ion pipes from rust.

Question 16

How can you remove hardness?

Answer 16

By adding sodium carbonate. The carbonate ions join onto the calcium ions and make an insoluble precipitate. Softening water with sodium carbonate is only suitable in certain circumstances-such as washing clothes.

Question 17

How can you remove hardness?

Answer 17

By an ion exchange column. The columns have lots of sodium (or hydrogen ions) and exchange them for calcium or magnesium ions in the water that runs through them.

Question 18

How can you remove hardness?

Answer 18

Scale is mainly calcium carbonate and can be dissolved by acid.