C1

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Describe phase 1 in the evolution of the atmosphere
Earth's surface originally molten - so hot atmosphere 'boiled away'. Cooled down and thin crust formed, with volcanoes still erupting. Volcanoes gave out the gases carbon dioxide, nitogen and water vapour. Water vapour condensing = oceons.
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Describe phase 2 in the evolution of the atmosphere.
Carbon dioxide atmosphere - green plants evolved.Carbon dioxide dissolved in oceons and removed by plants. Plants died and buried under layers of sediment. Carbon removed from air was 'locked' in sedimentary rocks as insoluble carbonates/fossil fuels
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Describe phase 3 in the evolution of the atmosphere
The build up of oxygen in the atmosphere (produced by photosynthesis) killed off early organiss and allowed complex organisms to evolve. Not much carbon dioxide left.
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What mixture of gases is Earth surrounded by?
The atmosphere (air), water vapour, 78% Nitrogen, 21% Oxygen, 1% Argon
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How is human activity adding small amounts of pollutants to the air?
Pollution from burning fuels in power stations and vehicles. Gases and particulates can be released by nature (volcanoes). Pollutants can harm us indirectly (enviroment) or directly (cause disease/death in people who breathe in large quantities).
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What are all substances made from?
Tiny particles called atoms.
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What are molecules?
Atoms joined together.
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What do almost all chemical reactions involve?
Atoms changing places. The atoms from the substance you start off with (reactants) rearrange themselves to form different chemicals (products).
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Is mass lost during a chemical reaction?
No, mass of reactants = mass of products.
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What are many hydrocarbons?
Fossil fuels formed from remains of dead plants and animals over millions of years. These fuels are drilled out out of the Earth and refines to make useful products.
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What is the only difference between different fossil fuels?
The size of hydrocarbons they contain.
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What is oxidation?
Any reaction where oxygen is added.
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What is reduction?
Any reaction where oxygen is lost.
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Where does the oxygen needed to burn hydrocarbons come from?
From the air, or in the form of pure oxygen. Hydrocarbon fuels burn more rapidly in pure oxygen.
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What are the three forms of carbon air pollution?
Carbon dioxide, carbon monoxide, particulate carbon.
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How is carbon dioxide removed from the atmosphere naturally?
Plants photosynthesising, dissolving in rainwater, seas, lakes, rivers.
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How does carbon dioxide pollute the atmosphere?
It increases the greenhouse effect, warming up the Earth and causing sea levels to rise.
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How is carbon monoxide produced?
When there's not enough oxygen in the burning of fuels (incomplete burning).
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How is particulate carbon produced?
When fuels burn incompletely.
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What does particulate carbon do?
Escapes into the atmosphere. Falls back to the ground and deposits as black dust (soot) which makes buildings appear dirty.
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Why do fuels contain lots of impurities (e.g traces of sulfur)?
Because they are extracted straight from the Earth's crust.
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How is sulfur dioxide produced?
When the fuel burns, the traces of sulfur burn too.When sulfur atoms burn, they combine with oxygen in air to produce sulfur dioxide.
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How is acid rain formed and why is it a problem?
When the sulfur dioxide emitted from vehicle engines and power stations react with the moisture in the clouds. Acid rain causes lakes to become acidic, killing plants and animals. It kills tress and damages buildings and statues made from some stones
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What are the two compounds known as nitrogen oxides?
Nitrogen monoxide and nitrogen dioxide.
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How is nitrogen pollution formed?
Fossil fuels burn at high temperatures so that nearby atoms in the air react with each other.Nitrogen in the air reacts with oxygen in the air to produce small amounts of nitrogen oxides. This happens in car engines.
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How is nitrogen dioxide formed?
Once the nitrogen monoxide is in the air, it will go on to react with more oxygen to produce nitrogen dioxide.
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What is the effect of nitrogen oxides?
They usually stay in the atmosphere until they react with moisture in the clouds. This produces a dilute nitric acid which eventually falls to the Earth as acid rain.
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What ways can you reduce pollution from power stations?
Use less electricity, reduce carbon dioxide emissions, most of the sulfur can be taken out of natural gas and fuel oil, when coal is burnt most sulfur dioxide/particulates can be removed from the flue gases before they're released into the atmosphere
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What is wet scrubbing?
Acidic sulfur dioxide is removed from flue gases by reacting with an alkali.
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What two types of alkali can be used in wet scrubbing?
Seawater (sulfure dioxide is dissolved producing carbon dioxide, water and dissolved sulfate), an alkaline slurry (sprayes onto the gases and the sulfure dioxide reacts to form a solid waste product).
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How can you reduce pollution from cars?
More efficient engines which burn less fuel, low-sulfur fuel, catalytic converters, legal limit on amount of polluting emissions (MOT test), use public transport
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What do catalytic converters do?
Convert nitrogen monoxide into nitrogen and oxygen (reduction reaction), and converts carbon monoxide into carbon dioxide (oxidation reaction).
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What alternatives are there to fossil fuels?
Biofuels (renewable energy source made from plants and waste. Said to be carbon neutral. Species lose habitat) and electric batteries (produce no exhaust gases but still use electricity)
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Other cards in this set

Card 2

Front

Describe phase 2 in the evolution of the atmosphere.

Back

Carbon dioxide atmosphere - green plants evolved.Carbon dioxide dissolved in oceons and removed by plants. Plants died and buried under layers of sediment. Carbon removed from air was 'locked' in sedimentary rocks as insoluble carbonates/fossil fuels

Card 3

Front

Describe phase 3 in the evolution of the atmosphere

Back

Preview of the front of card 3

Card 4

Front

What mixture of gases is Earth surrounded by?

Back

Preview of the front of card 4

Card 5

Front

How is human activity adding small amounts of pollutants to the air?

Back

Preview of the front of card 5
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