Air and Atmosphere

Question 1

Percentage composition of volume of nitrogen gas

Answer 1

78%

Question 2

Percentage composition of volume of oxygen gas

Answer 2

21%

Question 3

Percentage composition of volume of carbon dioxide

Answer 3

0.03%

Question 4

Percentage composition of volume of other gases, e.g. argon,
water vapour

Answer 4

0.97%

Question 5

How is air separated?

Answer 5

cooling to a liquid before fractional distillation

Question 6

source of pollutant SO2

Answer 6

• man-made cause: combustion of fossil fuels in motor vehicles, power stations and factories
• natural cause: volcanic eruptions

Question 7

source of pollutant Oxides of Nitrogen, NO or NO2

Answer 7

man-made cause: at high temperatures in car engines, nitrogen gas in air reacts with oxygen gas.
* natural cause: lightning activity

Question 8

source of pollutant Carbon Monoxide, CO

Answer 8

incomplete combustion of carbon-containing substances, e.g. charcoal, wood and petrol

Question 9

harmful effects of SO2 and NO or NO3

Answer 9

• irritate the eyes and lungs and cause breathing difficulties
• react with water in the atmosphere to form acid rain, which corrodes buildings and harms aquatic life and plants

Question 10

harmful effects of CO

Answer 10

prevents blood from carrying oxygen and can cause breathing difficulties and even death

Question 11

How does sulfur dioxide and nitrogen
oxides affect the environment?

Answer 11

They react with rainwater to form acid rain, destroying aquatic life and corroding buildings.

Question 12

Name the most abundant gas in the
atmosphere.

Answer 12

Nitrogen