10.3. Air quality and climate
A subsection of Chemistry, 0620, through 10. Chemistry of the environment
Listing 10 of 389 questions
Air is a mixture of gases. State the percentage of clean dry air which is oxygen. Give your answer to the nearest whole number.  % Oxygen and nitrogen are useful gases that can be obtained from air. Name the process used to separate oxygen and nitrogen from liquid air. State the property of oxygen and nitrogen that allows these gases to be separated using this process. Carbondioxide, CO2, is a covalent molecule. Complete the diagram to show the electron arrangement in one molecule of CO2. Show only the outer electrons. C O O  The graph shows the concentration of carbondioxide in the atmosphere over a 60‑year period, measured in parts per million . concentration of carbon dioxide / ppm year The data shown in the graph is of global concern. Explain why. Name the process in the carbon cycle by which plants remove carbon dioxide from the atmosphere. 
0620_w20_qp_41
THEORY
2020
Paper 4, Variant 1
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Table3.1 shows the average concentrations, in ng / 1000 cm3, of air pollutants in four different years. Table 3.1 year concentration of air pollutant in ng / 1000 cm3 carbon monoxide hydrocarbons oxides of nitrogen particulates sulfur dioxide 2.5 12.0 19.6 28.0 30.0 2.0 13.5 21.8 30.1 21.7 1.8 14.8 18.5 27.5 23.8 1.6 16.0 22.7 26.2 25.0 Name the oxide pollutant that has the highest concentration in 2021. Name the pollutant that shows a continuous decrease in concentration from 2019 to 2022. Calculate the average mass, in ng, of particulates in a 250 cm3 sample of polluted air in 2019.  mass = ng State one adverse effect of particulates on health. Particulates are formed by the incomplete combustion of hydrocarbons. State the meaning of the term incomplete combustion. Oxides of nitrogen contribute to acid rain. Choose from the list the pH value for an acidic solution. Draw a circle around your chosen answer. pH 5 pH 7 pH 9 pH 13 Complete the sentence about removing oxides of nitrogen from car exhausts by choosing two words from the list. agent catalytic compound converter distillation filter oxidising pump The emission of oxides of nitrogen from car exhausts is reduced by using a . Oxides of nitrogen can be formed by the action of bacteria on nitrates. Name the aqueous solution and the metal used in the test for nitrate ions. aqueous solution metal  Nitrogendioxide decomposes when heated. Nitricoxide and oxygen are produced. Complete the symbol equation for this reaction. NO2 2NO +  State the meaning of the symbol . 
0620_w23_qp_32
THEORY
2023
Paper 3, Variant 2
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Table3.1 shows the average concentrations, in ng / 1000 cm3, of air pollutants in four different years. Table 3.1 year concentration of air pollutant in ng / 1000 cm3 carbon monoxide hydrocarbons oxides of nitrogen particulates sulfur dioxide 5.3 22.0 15.6 19.0 20.0 4.1 13.5 14.8 20.1 18.2 5.8 14.8 22.7 23.5 16.2 2.6 18.0 10.9 26.2 14.0 Name the pollutant which has the highest concentration in 2019. Name the pollutant that shows a continuous decrease in concentration from 2019 to 2022. Calculate the average mass, in ng, of hydrocarbons in a 200 cm3 sample of polluted air in 2019.  mass = ng State one source of oxides of nitrogen in the air. Oxides of nitrogen contribute to acid rain. Give one other effect of oxides of nitrogen in the air. Unpolluted water has a neutral pH. Choose from the list the pH value of a neutral substance. Draw a circle around your chosen answer. pH 1 pH 6 pH 7 pH 14 Nitrogendioxide is an acidic oxide. Choose an oxide from the list which is also an acidic oxide. Tick (✓) one box. copper(oxide magnesium oxide phosphorus(oxide sodium oxide  Sulfurdioxide reacts with oxygen to produce sulfurtrioxide. Complete the symbol equation for this reaction. SO2 + 2SO3 State the meaning of the symbol . Sulfurtrioxide reacts with calciumoxide to produce calciumsulfate. Describe a test for sulfate ions. test observations  
0620_w23_qp_33
THEORY
2023
Paper 3, Variant 3
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Questions Discovered
389