The Hydrosphere

Question 1

What makes up the Earth’s hydrosphere?

Answer 1

Oceans, lakes, seas and rivers, it is mainly water with some dissolved compounds: salts

Question 2

How are crystals of ionic compounds arranged and how does this relate to their properties?

Answer 2

They are arranged in a regular lattice, held together by opposite forces of attraction between charged ions, they therefore have high melting and boiling points as lots of energy is required to break the ionic bonds in lattice

Question 3

What happens when ionic compounds are dissolved in water and how does this affect their ability to conduct electricity?

Answer 3

Ionic compounds do not conduct electricity when solid because the ions aren’t free to move, when dissolved however they can move and do conduct.

Question 4

What happens to some positive metals when an alkali is added to them?

Answer 4

They form a precipitate of an insoluble compound, the colour can be used to identify the ions in the compound

Question 5

What are the colours of the precipitates of:
Calcium
Copper
Iron(II)
Iron(III)
Zinc?

Answer 5

Calcium: White precipitate
Copper: Light blue
Iron(II): Green
Iron(III): Red-brown 
(All insoluble in excess)
Zinc: White (soluble in excess, giving a colourless solution)

Question 6

What is added to negative chloride, bromide, iodide and sulfate ions to identify them?

Answer 6

Dilute silver nitrate or dilute barium chloride

Question 7

What is added to negative carbonate ions to identify them?

Answer 7

Dilute acids and looking for fizzing