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This question is about pollutants - AQA - GCSE Chemistry Combined Science - Question 3 - 2020 - Paper 2

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This question is about pollutants. Waste water has harmful substances removed before being released into the environment. Complete the sentences. Agricultural was... show full transcript

Worked Solution & Example Answer:This question is about pollutants - AQA - GCSE Chemistry Combined Science - Question 3 - 2020 - Paper 2

Step 1

Agricultural waste water requires the removal of harmful

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Answer

microbes (bacteria/pathogens) and chemicals.

Step 2

Industrial waste water may require the removal of harmful

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Answer

microbes (bacteria/pathogens) and chemicals.

Step 3

How is sewage sludge treated before being released into the environment? Tick (✓) one box.

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Answer

Anaerobic digestion.

Step 4

Percentage decrease =

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Answer

The percentage decrease can be calculated using the formula:

ext{Percentage decrease} = rac{( ext{original} - ext{new})}{ ext{original}} imes 100

Where the original number of plastic bags was 8.0 billion and the new number is 1.3 billion. Thus,

ext{Percentage decrease} = rac{(8.0 - 1.3)}{8.0} imes 100 = rac{6.7}{8.0} imes 100 \ = 83.75 ext{ or approximately }84 ext{ %}

Step 5

Give one problem oxides of nitrogen cause.

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Answer

Respiratory problems or acid rain.

Step 6

Suggest why the mass of oxides of nitrogen produced from car engines increased and then decreased.

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Answer

Increased due to more cars on the road. Decreased due to improved efficiency of car engines and the introduction of catalytic converters.

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