Gases in the atmosphere paper 2

Question 1

Nitrogen percentage

Answer 1

78.1

Question 2

Oxygen percentage

Answer 2

21

Question 3

Argon percentage

Answer 3

0.9

Question 4

Carbon dioxide percentage

Answer 4

0.04

Question 5

How to prove that oxygen makes up approx 20 percent of air using copper

Answer 5

Air is pushed back and forth between two syringes and hot copper is in the middle
The copper is in excess and uses up the oxygen to form copper oxide
All the oxygen in the air is therefore used up, and so the volume of the air decreases by about 20% (the percentage of oxygen in air).

Question 6

How to prove that oxygen makes up approx 20 percent of air using iron

Answer 6

The iron reacts with the oxygen in the air (rusting).

As long as the iron and water are in excess, the total volume of air enclosed by the apparatus decreases by about a fifth (20%) over several days.

Question 7

How to prove that oxygen makes up approx 20 percent of air using phosphorus

Answer 7

The phosphorus is lit with a hot wire.

It reacts with the oxygen in the air and causes the water level in the bell jar to rise by about 20%

Question 8

Magnesium reacts with oxygen producing

Answer 8

a bright white flame leaving behind a white ash of magnesium oxide.

Question 9

Hydrogen reacts with oxygen in an

Answer 9

explosive reaction

Question 10

Sulfur reacts with oxygen producing a

Answer 10

blue flame

Question 11

When sulfur dioxide (SO₂) dissolves in water it forms an

Answer 11

acidic solution of sulfurous acid

Question 12

On heating metal carbonates thermal decompose into

Answer 12

metal oxides and carbon dioxide.

Question 13

copper carbonate –

Answer 13

copper oxide + carbon dioxide

green powder changes to a black powder

Question 14

Carbon dioxide (CO2) is a greenhouse gas - how does it contribute to global warming

Answer 14

It absorbs infra-red radiation and therefore warms the atmosphere. This leads to global warming.

This may cause climate change.