C1 - Air Quality

Question 1

What was Phase 1 of the evolution of the atmosphere?

Answer 1

Phase 1 was when the Volcanoes gave out gases.

Feedback:
1) Earth’s surface originally molten.
2) Was so hot that any atmosphere just ‘boiled away’ into space.
3 Things cooled down a bit, a thin crust formed, but volcanoes kept erupting.
4) Volcanoes gave out gases - carbon dioxide, water vapour and nitrogen.
5) Early atmosphere = mostly CO2 and water vapour, virtually no oxygen.
6) The oceans formed when the water vapour condensed when the Earth cooled.

Question 2

What was Phase 2 of the evolution of the atmosphere?

Answer 2

Phase 2 was when the Green Plants evolved and produced oxygen.

Feedback:

1) Evolved over most of the Earth - happy in CO2.
2) A lot of early CO2 dissolved in the oceans.
3) Green plants removed CO2, produced O2, by photosynthesis.
4) Plants dying = the carbon in the plants becomes ‘locked up’ in sedimentary rocks as insoluble carbonates and fossil fuels.

Question 3

What was Phase 3 of the evolution of the atmosphere?

Answer 3

Phase 3 was when Complex Organisms evolved.

Feedback:

1) The build up of oxygen killed off some early organisms that couldn’t tolerate it - allowed other complex organisms to evolve.
2) Virtually no CO2 left now.

Question 4

What is the chemical composition of the atmosphere?

Answer 4

The atmosphere contains 3 main elements:

78% Nitrogen
21% Oxygen
1% Argon
+ small quantities of other chemicals and compounds including CO2 and other gases plus water vapour.

Feedback:

Question 5

What gases did volcanoes give out?

Answer 5

Carbon dioxide, water vapour and nitrogen.

Question 6

What was the early atmosphere composed of?

Answer 6

Mostly CO2 and water vapour with virtually no oxygen.

Question 7

What did the evolved green plants do on earth?

Answer 7

Removed CO2, produced O2, by photosynthesis.

Question 8

What happens when plants die?

Answer 8

The carbon in the plants becomes ‘locked up’ in sedimentary rocks as insoluble carbonates and fossil fuels.

Question 9

What pollutants do humans add to the atmosphere?

Answer 9

Carbon dioxide, carbon monoxide, particulates, sulfur dioxide and nitrogen oxides.

Question 10

What causes acid rain?

Answer 10

Sulfur Dioxide.

Question 11

What are the negative affects of acid rain?

Answer 11

Acid rain pollutes rivers and lakes which kills the fish that people then catch and eat.

Question 12

What are all substances made from?

Answer 12

Tiny particles called atoms.

Question 13

What happens when atoms are joined together?

Answer 13

They make molecules.

Question 14

What do all chemical reactions involve?

Answer 14

Atoms changing places.

Feedback:

1) The atoms from the substance you start off with (the reactants) rearrange themselves to form different chemicals.
2) The new chemicals are called the products.

Question 15

What do majority of the fuels we use contain?

Answer 15

Hydrocarbons - carbon and hydrogen.

Question 16

What happens when a hydrocarbon burns?

Answer 16

The hydrogen atoms in the fuel combine with oxygen atoms from the air to make hydrogen oxide (otherwise known as water).

The carbon atoms in the fuel combine with oxygen atoms from the air to make carbon dioxide.

Question 17

What is an oxidation reaction?

Answer 17

Any reaction where oxygen is added.

Question 18

What is pure oxygen kept in?

Answer 18

Pressurised cylinders.

Question 19

What is pure oxygen used for?

Answer 19

Can be used in oxy-fuel welding torches.

Feedback:
1) The oxygen allows the fuel top burn more rapidly so a higher temperature can be reached.

Question 20

What are fossil fuels used for?

Answer 20

They are burnt to release energy. They are used to power vehicles and to produce electricity in power stations.

Feedback:
1) The carbon-based products of burning fossil fuels often pollute the atmosphere.