C6.3 Flashcards
What is the atmosphere made up of in the present?
Mainly nitrogen, oxygen and argon
Smaller percentages of carbon dioxide and water vapour
What was the atmosphere like in the past?
Substances in the atmosphere were thought to have come from volcanoes
They release huge volumes of water vapour and carbon dioxide
As water vapour condensed oceans were formed so the atmosphere was left with mainly carbon
Small amounts of ammonia, methane but little oxygen
How old is the earth?
4.54 billion years old
How did the atmosphere change overtime?
When plants and algae appeared, photosynthesis reduced the volume of carbon dioxide and released oxygen into the atmosphere
At first oxygen reacted with metals in rocks to produce metal oxides
Later as most metals became oxidised free oxygen began to accumulate in the atmosphere
What are pollutants?
Substances released just to the environment that may harm living things
Atmospheric pollutants are relied into the air
What are some pollutants released into the atmosphere?
Carbon monoxide
Particulates
Oxides of nitrogen
Sulfur dioxide
How is carbon monoxide released into the atmosphere?
Produced during incomplete combustion of fuels that contain carbon
Can happen when coal, wood, or natural gases are burned in a poor supply of air
Why is carbon monoxide harmful?
Toxic gas that is colourless and has no taste or smell
When breathed in it attaches to haemoglobin so less oxygen can bind to the hasmoglobin
Less oxygen is transported around the body
Can cause difficulty in breathing, drowsiness and even death
What are particulates and how are they released into the atmosphere?
Small particles
Produced in industrial processes, metal extraction
Produced by incomplete combustion and in vehicle engines
Why are particulates harmful?
They seethe deep in the lungs when breathed in
Causes diseases such as bronchitis and increases chance of heart disease
How are nitrogen dioxide produced?
Even though nitrogen and oxygen are the main gases in the air, they don’t react
They do at high temperatures in vehicle engines to form nitrogen monoxide
This is then oxidised in air to form nitrogen dioxide
How are nitrogen dioxide harmful?
Nitrogen dioxide dissolves in moisture clouds to form an acidic solution
This falls as acidic rain which erodes stonework and corrodes metals
Can kill trees and living things in river and lakes
How is sulfur dioxide formed?
Fossil fuels naturally contains small amounts of sulfur compounds
These impurities from sulfur dioxide when the fuel is burnt
Why is sulfur dioxide harmful?
It also causes acid rain which can cause breathing difficulties
What is greenhouse effect?
Greenhouse gases (CO2, methane) absorb infrared radiation radiated by the earths surface and emit it in al directions
This keeps the earth and atmosphere warm enough for living things to exist
