C1 - Air Quality

Question 1

What is a hydrocarbon?

Answer 1

A molecule made up of only hydrogen and carbon atoms.

Question 2

Name the main element that makes up coal.

Answer 2

Carbon. Coal may contain some other elements but these are just impurities.

Question 3

Atoms can disappear completely in some chemical reactions - true or false?

Answer 3

False - They can just be rearranged to make new products - the mass will always remain the same.

Question 4

What effects does acid rain have on the environment?

Answer 4

• pollutes rivers and seas which kills the fish etc.
• erodes buildings especially those made of limestone/sandstone.
• kills trees (deforestation)

Question 5

What three main gases is the current atmosphere made of and in what proportions are they found?

Answer 5

Nitrogen = 78%
Oxygen = 21%
Argon = 1%
Others = CO2, Water Vapour and other gases

Question 6

When a hydrocarbon fuel burns, with what substance in the air do the hydrogen and carbon atoms combine?

Answer 6

Oxygen.

- to make water and carbon dioxide

Question 7

What removes carbon dioxide from the atmosphere?

Answer 7

Photosynthesis.

CO2 can also dissolve in rain water and in seas, lakes and rivers.

Question 8

What atoms make up carbon monoxide? Under what condition is carbon monoxide produced?

Answer 8

1 Carbon and 1 Oxygen atom.

During incomplete combustion.

Question 9

What are particles of carbon otherwise known as and what kind of pollution do they cause?

Answer 9

Carbon particulates.

They cause soot on buildings when they lower in the atmosphere.

Question 10

Describe briefly how the pollutant Sulfur Dioxide is produced.

Answer 10

Sulfur is an impurity within many fossil fuels so when fuel is burnt, Sulfur is released which then combined with oxygen forming Sulfur Dioxide which ends up in the atmosphere.

Question 11

Give an alternate method of power other than biofuels and fossil fuels.
State the advantage and disadvantage of this method.

Answer 11

Electric Batteries.

• no exhaust gases
• electricity is made by burning fossil fuels so you don’t get rid of the pollution it is just created somewhere else (the power station)

Question 12

When hydrocarbons burn in plenty of oxygen, the atoms involved rearrange themselves into carbon dioxide and what else?

Answer 12

Water (H2O)

Question 13

What effect do nitrogen oxides have on the environment?

Answer 13

Turns into acid rain by reacting with moisture in the clouds to produce dilute nitric acid.

• Kills fish and animals
• Erodes buildings and statues
• Kills trees

Question 14

Give the formulas of nitrogen monoxide and nitrogen dioxide.

Answer 14

Nitrogen Monoxide=NO
Nitrogen Dioxide = NO2
Nitrogen Oxides = NOx

Question 15

What do catalytic converters do?

Answer 15

They reduce the amount of harmful pollutants being released into the atmosphere.
They complete reduction and oxidation reactions.
Reduction Reactions:
- nitrogen monoxide is turned into nitrogen and oxygen.
Oxidation Reactions:
- carbon monoxide is turned into carbon dioxide.

Question 16

Name one result of pollution which causes direct harm to humans, and one which causes indirect harm.

Answer 16

Direct harm - Those who breath in large quantities e.g CO can lead to death as it reduces the amount of O2 the blood can carry.
Indirect harm - Sulfur dioxide can cause acid rain, which pollutes rivers and lakes thereby killing the fish which people catch and eat.

Question 17

Name two things that everyone could do in order to reduce carbon dioxide pollution.

Answer 17

• use more public transport

- switch off lights so not to waste electricity

Question 18

How do MOT tests help combat air pollution? And how often do you have to have one?

Answer 18

They prevent cars being driven if the emissions are above the legal limit.
Each car is checked once a year apart from new cars which are given a 3yr allowance.

Question 19

What are biofuels?

Answer 19

They are renewable energy sources made from plants and waste.
They only produce CO2 and H2O when burned.

Question 20

For a long time, the Earth’s early atmosphere was mostly CO2. Where did this CO2 come from?

Answer 20

Volcanoes. When the volcanoes erupted they let out large quantities of CO2. In the early atmosphere there was also few methods of removing it too.

Question 21

What does it mean when biofuels are said to be ‘carbon neutral’?

Answer 21

That the plants used to make the fuel take in as much CO2 as the fuel gives out when burnt.

Question 22

Give a disadvantage of biofuels.

Answer 22

Forests are sometimes cut down to grow the plants for biofuel which destroys some species natural habitats.

Question 23

Describe how nitrogen dioxide is produced when fossil fuels are burnt.

Answer 23

Fossil fuels are burnt at very high temperatures such that nearby atoms in the air react with each other. Nitrogen in the air reacts with oxygen in the air to produce the compounds known as nitrogen oxides - nitrogen monoxide and nitrogen dioxide.
This happens in car engines.
Nitrogen oxides are pollutants which go straight into the atmosphere.