Oxygen And Oxides

Question 1

Percentage of oxygen in air

Answer 1

Nitrogen, 78%
Oxygen, 21%
Argon, 0.9%
Carbon dioxide, 0.037%

Question 2

Thermal decomposition

Answer 2

Heat up carbonate, breaks down into metal oxide and carbon dioxide

Question 3

Determine % of oxygen in air

Answer 3

Copper between 2 gas syringes
Heat copper, pass air over copper
79% of air should be left

Question 4

How to make oxygen

Answer 4

Catalysed decomposition of hydrogen peroxide
Manganese dioxide speeds up reaction
Over water

Question 5

Reactions of magnesium in oxygen

Answer 5

Magnesium oxide
Bright white light
Alkali oxide

Question 6

Reaction of carbon in oxygen

Answer 6

Carbon dioxide
Acidic oxide
Orange flame

Question 7

Reactions of sulphur in oxygen

Answer 7

Sulphur dioxide
Blue flame
Acidic oxide

Question 8

Rusting

Answer 8

Iron oxide

Oxygen and water=>hydrated iron (3) oxide

Question 9

Prevent rust

Answer 9

Barrier
Paint, coating
Oiling, greasing

Sacrificial metals
Zinc coating, galvanising
Oxidised instead, more reactive