What is the % of nitrogen in air?

• 75%

• 71%

• 78%

• 60%

Which is not a use of oxygen?

• In oxyacetylene torch used in welding

• As breathing aid in hospitals

• Remove impurities in steel-making

• Produce ammonia for making fertiliser

Motorised vehicles are the major source of which pollutants? Tick all that apply.

• sulfur dioxide

• oxides of nitrogen

• carbon monoxide

• particulates (unburnt carbon)

Which pollutant can cause brain damage?

• Lead compounds

• Particulate matter

• Sulfur dioxide

• Nitrogen oxides

Which air pollutants can cause acid rain?

• Nitrogen oxides and sulfur dioxide

• Sulfur dioxide and carbon monoxide

• Nitrogen oxides and ozone

• Sulfur dioxide and ozone

In the fractional distillation of liquid air,

• air is warmed so that it is liquefied.

• nitrogen is collected first as it has the highest boiling point.

• CO₂ and H₂O are removed before cooling.

• air is cooled to a temperature of absolute zero.

Which reaction does not take place in a catalytic converter?

• 2CO + O₂ -> 2CO₂

• N₂ + 2CO₂ -> 2NO + 2CO

• 2NO₂ + 4CO -> N₂ + 4CO₂

• 2NO₂ -> N₂ + 2O₂

Which catalyst is used in the catalytic converter?

• iron

• gold

• platinum

• technetium

What is the key chemistry principle behind the catalytic converter?

• neutralisation

• redox

• electrolysis

• fractional distillation

Which statements about pollutants are correct?

1 Carbon monoxide is responsible for the production of ‘acid rain’.

2 Oxides of nitrogen are present in car exhausts.

3 Sulfur dioxide can be produced by the combustion of fossil fuels.

• 1, 2 and 3

• 1 and 2 only

• 1 and 3 only

• 2 and 3 only