Chemistry P1

What is the atmosphere?
The Earth is surrounded by a thin layer of gases called the atmosphere. Air forms part of the atmosphere. It is a mixture of different gases consisting of small molecules with large spaces between them.
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What is the atmosphere made up of?
Oxygen (O2) - 21%, Nitrogen (N2) - 78%, Carbon Dioxide (CO2) - 0.04%, Argon (Ar) - 1%, Water Vapour (H2O) - 0-4%
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What was the Earth's atmosphere like 4 million years ago?
The earliest atmosphere contained ammonia, water vapour and carbon dioxide. These gases came from inside the Earth and were often released through the action of volcanoes
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What was the Earth's atmosphere like 3 million years ago?
As the temperature of the planet fell, the water vapour in the atmosphere condensed to form oceans and seas
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What was the Earth's atmosphere like 2 million years ago?
The evolution of photosynthesising organisms started to reduce the amount of carbon dioxide and increase the amount of oxygen in the atmosphere
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What was the Earth's atmosphere like 1 million years ago?
Carbon from carbon dioxide became locked up in sedimentary rocks as carbonates and fossil fuels after dissolving in the ocean
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Name a way to reduce pollution.
Make people convert their engines to lean burn, switch the power station fuel from coal to gas, Introduce a congestion charge, Ban new cars with big engines, Build a new electric tram system, Introduce a tax on using energy inefficiently
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What is a catalytic converter?
Catalytic converters use a platinum and rhodium catalyst with a high surface area. This increases the rate of reaction of carbon monoxide and unburnt fuel from exhaust gases with oxygen from the air.
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What is the chemical reaction for a catalytic converter?
NO(g) +CO(g) => ½ N2(g) + CO2(g)
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What is wet scrubbing?
Wet scrubbing involves the removal of sulphur dioxide from flue gases before it escapes from the power station chimney
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What are the two processes of wet scrubbing?
1. spraying the flue gases with seawater droplets which react with the sulphur dioxide 2. using powdered lime (calcium oxide) mixed with water to form an alkaline slurry.
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What is combustion?
Combustion is a chemical reaction that occurs when fuels burn, releasing energy as heat. It is an example of oxidation
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What does combustion require?
Fuel, oxygen and a source of hear to raise the temperature of the mixture
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What is complete combustion?
Fuel burns completely to form water (H2O) and Carbon Dioxide (CO2) only
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What is the chemical reaction to show complete combustion?
Fuel + Oxygen => Carbon Dioxide + Water
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What is incomplete combustion?
When there is limited oxygen present. Products are Carbon Dioxide (CO2), Water (H20), Carbon Monoxide (CO) and unburned Carbon (C)
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What is the chemical reaction to show incomplete combustion?
Fuel + Oxygen => Carbon Monoxide + Water + Carbon Monoxide
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What is an exothermic reaction?
These are reactions that transfer energy to the surroundings
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What are some examples of an exothermic reactions?
burning, neutralisation reactions between acids and alkalis, the reaction between water and calcium oxide
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What is an endothermic reaction?
These are reactions that take in energy from the surroundings
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What are some examples of an endothermic reactions?
electrolysis, the reaction between ethanoic acid and sodium carbonate, the thermal decomposition of calcium carbonate in a blast furnace
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Card 2

Front

What is the atmosphere made up of?

Back

Oxygen (O2) - 21%, Nitrogen (N2) - 78%, Carbon Dioxide (CO2) - 0.04%, Argon (Ar) - 1%, Water Vapour (H2O) - 0-4%

Card 3

Front

What was the Earth's atmosphere like 4 million years ago?

Back

Preview of the front of card 3

Card 4

Front

What was the Earth's atmosphere like 3 million years ago?

Back

Preview of the front of card 4

Card 5

Front

What was the Earth's atmosphere like 2 million years ago?

Back

Preview of the front of card 5
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