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53 Cards in this Set
- Front
- Back
What is the atmosphere?
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The atmosphere is a thin layer of gases surrounding the Earth
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What is the composition of the atmosphere?
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78% nitrogen
21% oxygen 1% argon |
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What's the first stage of the evolution of the atmosphere?
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The early atmosphere was created by volcanic activity and consisted mainly of carbon dioxide and water vapour
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What's the second stage of the evolution of the atmosphere?
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As the Earth cooled, the water vapour condensed and this process formed the oceans
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What's the third stage of the evolution of the atmosphere?
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Simple photosynthetic organisms evolved in the oceans, adding oxygen to the atmosphere and removing carbon dioxide
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What's the final stage of the evolution of the atmosphere?
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Some carbon dioxide was removed due to it dissolving in the oceans and forming sedimentary rocks and fossil fuels
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What do pollutants harm?
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Environment and health
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How does carbon dioxide harm the environment?
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It's a greenhouse gas, it traps heat in the Earth's atmosphere
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How do nitrogen oxides harm the environment/humans?
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1)They cause acid rain
2)Cause breathing problems and can make asthma worse |
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How does sulfur dioxide harm the environment?
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It causes acid rain
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How do particulates harm the environment/humans?
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1)Make buildings dirty
2)Can make asthma and lung infections worse if inhaled |
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How does carbon monoxide harm humans?
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It prevents the blood from carrying oxygen. It can be fatal
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What does 20ppb of sulfur dioxide mean?
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It means that for every 1000000000 molecules of air, 20 molecules will be sulfur dioxide
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Give an example of why you should repeat measurements
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The concentration of nitrogen oxides from cars may change depending on the time of day, amount of traffic and the weather.
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What do repeat measurements allow chemists to do?
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They'll allow them to calculate a mean which will give a good estimate of the true value of the concentration of the pollutant
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What are three natural processes that remove carbon dioxide from the atmosphere?
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1)Photosynthesis
2)Dissolves in the oceans 3)Forms sedimentary rocks and fossil fuels |
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What are elements made of?
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Tiny particles called atoms
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How do compounds form?
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Compounds form when the atoms of two or more different elements chemically combine
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What does the formula show?
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It shows different elements that make up a compound and the number of atoms of each element in one molecule
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What does "mass is conserved" mean?
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No atoms are lost or made in a chemical reaction, so the total number of products and the total number of reactants are the same
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What is combustion?
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Combustion (burning) is a chemical reaction.
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When does combustion occur?
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Combustion occurs when a fuel reacts with oxygen and energy is released.
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Because the fuel reacts with oxygen, combustion is what?
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A type of oxidation
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What is coal mainly made up of?
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Carbon
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What does one atom of carbon and one molecule of oxygen produce?
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It produces carbon dioxide
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When does complete combustion occur?
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Complete combustion occurs when there's enough oxygen present for a fuel to burn completely
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What compounds do petrol, diesel and fuel oil mainly consist of?
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Hydrocarbons
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What atoms do hydrocarbons contain?
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They contain only hydrogen and carbon atoms
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What do hydrocarbons produce when burned in air?
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They produce carbon dioxide and water
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When does incomplete combustion occur?
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Incomplete combustion occurs when a fuel is burned and there's not enough oxygen
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What could be produced by incomplete combustion (depending on the amount of oxygen present)?
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Carbon particulates (C) or Carbon monoxide (CO)
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Where does incomplete combustion occur?
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Incomplete combustion occurs in car engines
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What do exhaust emissions contain?
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They contain carbon particulates and carbon monoxide as well as carbon dioxide
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What can coal contain when burned?
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Coal can contain sulfur, so sulfur dioxide is released when burned
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What is SO2?
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Sulfur dioxide
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What can happen during the combustion of fuels at high temperatures?
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It can cause nitrogen in the atmosphere to react with oxygen, which causes nitrogen monoxide (NO)
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What happens to nitrogen monoxide when it's oxidised?
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It produces nitrogen dioxide (NO2)
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What causes NOx?
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When NO and NO2 occur together
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How can power station emissions be reduced?
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1)Using less electricity
2)Removing sulfur and toxic chemicals from gas, coal and oil before burning 3)Using alternative renewable energy sources |
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Give examples of renewable energy sources.
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1)Wind
2)Solar 3)Hydroelectric 4)Wave 5)Geothermal ect. |
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How can you remove sulfur dioxide from chimneys?
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By wet scrubbing with either a spray of calcium oxide and water or using seawater
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How can car emissions be reduced?
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1)Using low-sulfur fuel in a car with a modern fuel-efficient engine
2)Legal limits for exhaust emissions, enforced by MOT 3)Using public transport 4)Cars with catalytic converters |
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What do catalytic converters do?
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They reduce carbon monoxide and nitrogen monoxide in the engine exhaust gases
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Carbon monoxide + oxygen -->...
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Carbon dioxide
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Nitrogen monoxide + carbon monoxide -->...
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Nitrogen + carbon dioxide
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Why is it difficult to reduce emissions?
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Because we would need to burn fewer fossil fuels. This would be very hard since the population of the world is increasing every year and so is the demand of energy
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What can be used instead of fossil fuels to power cars?
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Biofuel
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What's a disadvantage with biofuel?
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It uses up valuable farmland
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How is combustion a type of oxidation?
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Because the fuel reacts with oxygen
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What does the term hydrocarbon mean?
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A hydrocarbon is a compound made only from hydrogen and carbon
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Give three ways in which to reduce power station emissions
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1)Using less electricity
2)Removing sulfur from the fuel being used 3)Removing sulfur dioxide and particulates from the gases released by the power station |
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Give four ways to reduce pollution pollution from cars.
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1)More efficient engines
2)Low-sulfur fuels 3)Catalytic converters 4)Public transport 5)Walking or cycling 6)Legal limits for emissions |
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Explain how NOx gases are formed
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Atmospheric nitrogen is oxidised by atmospheric oxygen at high temperatures to form nitrogen monoxide (NO),which is further oxidised to form nitrogen dioxide (NO2)
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