3The Earth’s Atmosphere 25/03/2017Present day atmosphere contains 78% nitrogen, 21% oxygen, 1% noble gases and about 0.03% CO2Carbon dioxide, water vapourOxygenNitrogenNoble gases
4Air25/03/2017Air is a mixture of different gases consisting of small molecules with large spaces between them:
5Evolution of the Earth’s Atmosphere 25/03/201725/03/2017CarbondioxideMethaneAmmoniaOxygenNitrogenOthersPresent day atmosphere contains 78% nitrogen, 21% oxygen, 1% noble gases and about 0.03% CO24 Billion years3 Billion years2 Billion years1 Billion yearsPresent day
6Evolution of the Earth’s Atmosphere 25/03/201725/03/2017Volcanic activity releases CO2, methane, ammonia and water vapour into the atmosphere. The water vapour condenses to form oceans.Some of the oxygen is converted into ozone. The ozone layer blocks out harmful ultra-violet rays which allows for the development of new life.4 Billion years3 Billion years2 Billion years1 Billion yearsPresent dayGreen plants evolve which take in CO2 and give out oxygen. Carbon from CO2 becomes locked up in sedimentary rocks as carbonates and fossil fuels. Methane and ammonia react with the oxygen and nitrogen is released.
7Carbon dioxide in the atmosphere 25/03/201725/03/2017The amount of CO2 in the atmosphere is affected by 3 things:1) Geological activity moves carbonate rocks deep into the Earth and they release ______ _______ into the atmosphere during volcanic activity.2) When fossil fuels are burned the carbon contained in them reacts with _____ to form CO2.3) Increased CO2 in the atmosphere causes a reaction between it and _______. These reactions do not remove ALL of the new CO2 so the greenhouse effect is still getting _______!Words – oxygen, seawater, carbon dioxide, worse
8Pollution What happens to pollution? 25/03/2017What happens to pollution?Carbon dioxide causes global warming but some of it can be removed by plants (photosynthesis) or reactions with seawater.Sulfur dioxide and nitrogen dioxide cause acid rain which damages trees and buildings.Particulates (like in smog) can make buildings dirty and worsen breathing difficulties.
9Pollution Humans pollute the Earth in a number of ways: Pollutant 25/03/2017Humans pollute the Earth in a number of ways:PollutantHarmful to...Why?Carbon dioxideEnvironmentNitrogen oxidesEnvironment + humansSulfur dioxideParticulates (e.g. Smoke)Carbon monoxideHumansA greenhouse gas that causes global warmingCauses acid rain and makes asthma/breathing problems worseCauses acid rainMakes buildings dirty and makes asthma worseDisplaces oxygen in red blood cells that can result in death
11Fuels25/03/2017Fuels are substances that can be used to release useful amounts of energy when they burn, e.g.WoodGasOilCoalThese fuels are called “fossil fuels” and are described as being “non-renewable”. The main element in these fuels is Carbon.
12Burning Hydrocarbons25/03/2017Oil, petrol and diesel are all examples of HYDROCARBONS. A hydrocarbon is a compound made up of carbon and hydrogen.Burning hydrocarbons will produce water, carbon dioxide and energy:CHOOHCOMethaneOxygen+Carbon dioxideWater+In this reaction the hydrocarbon is “oxidised” (“oxidised” means that oxygen has been added and it’s the opposite of reduced).
13More information on oxygen 25/03/2017Fuels need oxygen to burn. The more oxygen they have, the quicker they will burn. This is the principle behind oxy-acetylene torches:
14Other products of burning fuels 25/03/2017SOSulphur dioxideSulphur dioxide:SOSulphurOxygen+Nitrogen monoxideNOOxygen+ONitrogenNNitrogen monoxide:Nitrogen monoxide can be further oxidised to make nitrogen dioxide (Nitrogen monoxide and dioxide are jointly referred to as NOx):OOxygen+Nitrogen monoxideNNitrogen dioxideNO
15Conservation of mass in reactions 25/03/201725/03/2017In any reaction the total mass of products is the same as the total mass of the reactantsExample 1 – Magnesium oxide and hydrochloric acidMgOHCl1 x magnesium, 1 x oxygen, 2 x hydrogen and 2 x chlorine atomsAlso 1 x magnesium, 1 x oxygen, 2 x hydrogen and 2 x chlorine atomsExample 2 – Burning methaneCHO
16Incomplete Combustion 25/03/2017As well as producing carbon monoxide, incomplete combustion can also produce soot:Little oxygen:CHMethaneOOxygen+WaterCarbon“Soot”
17Burning Fossil Fuels25/03/201725/03/2017Burning fossil fuels like oil and coal causes pollution.Oil contains carbon:CHOCarbon dioxide is a “greenhouse gas” – it helps cause global warmingCoal contains carbon, sulfur and other particles:sulfur + oxygen sulfur dioxideSulfur dioxide causes acid rain. Other particles can cause “global dimming” – sunlight is absorbed by the particles in the atmosphere.
18Summary of pollutants25/03/2017Each of the following chemicals is a product of burning fossil fuels. For each one summarise how it is made and what harm it causes:COCarbon dioxideNitrogen monoxideNOCCarbon monoxideOOHWaterSOSulfur dioxideCCarbonNitrogen dioxideON
19C1.3 Improving Air Quality 25/03/2017C1.3 Improving Air Quality
20Removing Pollution There are many ways pollution can be reduced: 25/03/2017There are many ways pollution can be reduced:Use less electricity/central heatingRemove toxic chemicals before or after they are burntUse alternative energy sources, e.g. wind power
21Removing Sulfur25/03/201725/03/201725/03/2017Sulfur dioxide is clearly bad for the environment so it’s a good idea to remove as much sulfur as possible:Vehicles can remove sulfur from fuels before they are burned.Power stations can remove sulfur dioxide from waste gases after combustion.
22Wet Scrubbing25/03/2017“Wet scrubbing” is a term used to describe the removal of sulfur dioxide and other particles using seawater or an alkaline spray:Step 1 – the dirty gas is fed in through the top.Step 3 – the mixture is fed into a cyclone area where the slurry is collected at the bottom of the device.Step 2 – the “scrubbing liquid” (seawater or alkaline spray) is fed in through the side.
23Reducing Pollution from vehicles 25/03/2017A number of suggestions:1) Buy a new, smaller, more efficient car2) Use legal limits (e.g. An MOT) to enforce lower emissions3) Use low sulfur fuels or convert your car to run on biodiesel4) Make sure your car has a catalytic converter:Carbon monoxide + oxygen carbon dioxideNitrogen monoxide + carbon monoxide nitrogen + carbon monoxide5) Use the train or a bus!
24Alternative Fuels25/03/2017Car makers are currently researching two alternatives for petrol and diesel-powered cars. What are the advantages and disadvantages of each?Electric carsAdvantages:Disadvantages:Biofuel carsAdvantages:Disadvantages:
25Making choices about pollution 25/03/2017Choices concerning fighting pollution can be made on many levels:Internationale.g. The Kyoto protocol in 1997Nationale.g. Car tax system, subsidies for greener technologyLocale.g. Recycling schemes, transport, congestion chargesPersonale.g. Recycling, individual travel, reducing energy usage in the home etc