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| Questão | Responda |
| what gases are the atmosphere mainly made up of? | Nitrogen, Oxygen and Argon, water vapor, carbon dioxide and other gases |
| what percentages of nitrogen, oxygen and argon are there in the atmosphere? | nitrogen - 78% oxygen - 21% argon - 1% |
| what is released into the atmosphere by human activity? | -gases -particulates |
| name an environmental process that can add gases and particulates to our atmosphere | volcanic eruptions |
| how was the Earths early atmosphere formed and what did it mainly consist of? | it was formed by volcanic eruptions and mainly consisted of carbon dioxide and water |
| how were oceans formed when the Earth cooled? | the water vapor condensed |
| how did the evolution of photosynthesizing organisms change the atmosphere? | they added oxygen and removed carbon dioxide |
| as well as photosynthesis how else was CO2 removed from the atmosphere and what did the CO2 then form? | the carbon dioxide was removed by dissolving in the oceans, this then formed sedimentary rocks and this lead to the formation of fossil fuels |
| what have humans added to the atmosphere to change its composition? | -carbon monoxide -nitrogen oxides -sulfur dioxide -carbon dioxide (extra) -particulates |
| what can human released pollutants do to humans? (give an example) | carbon monoxide reduces the amount of oxygen that the blood can carry |
| how can human released pollutants affect animals? (give an example) | Sulfur dioxide causes acid rain (fish die, indirectly affect humans) |
| how are the concentrations of pollutants measured in the air? | by using PPB (parts per billion) or PPM (parts per million) |
| why is it important to repeat measurements of pollutant concentration? | the concentration could increase/decrease at different points in the day (more cars producing pollutants in the day than at night) and by repeating the measurement you can calculate a mean, a good estimate of the true value |
| what particles are elements made from? | atoms |
| how do molecules form? | atoms join together |
| does each element has a unique atom? | yes |
| how do compounds form? | when two or more atoms chemically combine |
| what happens to a reactant to form a product? | they are rearranged by separation and then being joined in a different way |
| what does it mean when someone says that mass is conserved in a chemical reaction? | no atoms are created or destroyed and therefore the mass of the product is the same as the mass of the reactants |
| what is coal mainly made up of? | carbon dioxide |
| what fuels are mainly compounds of hydrogen and carbon? | -petrol -diesel fuel -fuel oil |
| when fuels burn what combines with atoms of oxygen to produce carbon dioxide and/or water? | carbon and/or hydrogen |
| what happens when a fuel reacts with oxygen? | oxidation |
| what is a loss of oxygen an example of and what does this mean? | it is an example of reduction and this means that combustion reactions involve oxidation |
| what is oxidation? | when a substance gains oxygen |
| why do fuels burn more rapidly in pure oxygen than in air? | because there are more oxygen for it to react with |
| can oxygen be obtained from the atmosphere and what can it be used to support? | yes. it can be used to support combustion |
| why is sulfur dioxide produced is a fuel containing sulfur is burnt? | the sulfur reacts with the oxygen |
| what compounds are formed when burning fossil fuels? | -carbon dioxide -sulfur dioxide -carbon monoxide and carbon particulates (incomplete burning) -nitrogen oxides (oxygen + nitrogen in engines) |
| what are the chemical formulas for -carbon monoxide -carbon dioxide -sulfur dioxide -nitrogen monoxide -nitrogen dioxide -water? | -CO -CO2 -SO2 -NO -NO2 -H2O |
| how is nitrogen monoxide formed? | by combustion of fuels in the air |
| what is nitrogen oxide oxidized into? | nitrogen dioxide |
| where do -particulate carbon -sulfur dioxide -carbon dioxide go after combustion? | -particulate carbon is deposited on surfaces -sulfur dioxide react with water and oxygen to produce acid rain -carbon dioxide is used in photosynthesis or is dissolved in the sea |
| how can we reduce pollution from burning fossil fuels in power stations? | -use less electricity -remove sulfur dioxide from flue gasses emitted by coal burning power stations |
| how is the acid gas, sulfur dioxide removed from glue gases? | -using an alkaline slurry (e.f. a spray of calcium oxide and water) -sea water |
| what is the only way of producing less carbon dioxide? | burn less fossil fuels |
| how can atmospheric pollution caused by exhaust emissions be reduced? | -burning less fuel (more efficient engines) -using low sulfur fuels -using catalytic converters -make more people use public transport -having legal limits of exhaust emissions |
| what does a catalytic converter do? | it reduces nitrogen monoxide to just nitrogen by loss of oxygen, and carbon monoxide to carbon dioxide by gain of oxygen |
| what other things can we use as alternatives to fossil fuels, what are their problems? | -electricity (must be produced renewably) -biofuels (they use up valuable farm land) |
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