Module C1 - Air Quality Flashcards
What caused the carbon dioxide levels to decrease?
Green plants evolved and took in a lot of carbon dioxide, for photosynthesis, and produced oxygen. Some of the carbon dioxide also dissolved into the oceans. When plants died and were buried under layers of sediment, the carbon they had removed from the air became locked up in sedimentary rocks as fossil fuels and insoluble carbonates.
What is the current atmosphere made up of?
Nitrogen - 78%. Oxygen - 21%. Argon - 1%.
How do pollutants directly harm humans?
They can cause disease or death. For example, carbon monoxide reduces the amount of oxygen that the blood can carry and this can lead to flu like symptoms and death.
How do pollutants directly harm people?
They can damage the environment. For example, sulfur dioxide can cause acid rain which contaminates fish and we eat this. Other pollutants can lead to climate change, including carbon dioxide.
What are fossil fuels formed from?
The remains of dead animals and plants over millions of years.
When hydrocarbons burn, what do they produce?
Hydrogen oxide and carbon dioxide.
What is meant by oxidation?
When oxygen is added to a reaction. Combustion is an oxidation reaction.
What is meant by a reduction reaction?
Where oxygen is lost in a reaction.
Where can pure oxygen be obtained from?
It is obtained from the atmosphere and kept in pressurised containers. It can then be used for oxy-welding torches. The oxygen allows the fuel to burn more rapidly so a higher temperature can be reached.
When is carbon monoxide produced?
If there isn’t enough oxygen available when fuels burn. This is incomplete combustion. It is very poisonous and can lead to death.
How are carbon particulates formed?
When fuels burn incompletely. If they escape into the atmosphere, they float around until they deposit themselves as soot which makes buildings look dirty.
What was the early atmosphere made up of?
Carbon dioxide and water vapour, with virtually no oxygen.
