The Atmosphere and Fractional Distillation of Air

• Air contains many useful industry products like nitrogen, methane and oxygen, so can be fractionally distilled to obtain them.

1) Air is filtered to remove dust.

2) The air is cooled to -200 degrees, where it is liquid.

3) During this cooling, water vapour condenses and is removed.

4) CO2 freezes into a solid, and is removed.

5) The remaining fractions are argon and oxygen, which have similar boiling points so need further distilling for them to become separate. 

• Primordial Soup states that millions of years ago, hydrogen, methane, ammonia and nitrogen were all in the atmosphere
• Lightining struck and caused reactions between them that caused amino acids to form
• The amino acids eventually formed organic matter and evolved into organisms

Miller and Urey

• Miller and urey tried to prove Primordial Soup by sealing the gases in a container for a week with an electric charge supplied
• They found that some amino acids were made, but not as many as there are on earth today, suggesting the theory is along the right lines, but not completely correct.

• Millions of years ago, the atmosphere was mainly CO2
• Now it is 78% nitrogen, 21% oxygen and the rest are impurities like methane, water vapour etc.
• The earths crust used to be so hot that any atmosphere used to boil into space.
• Eventually it cooled and allowed the volcanoes to give out gases like CO2 and N2. 
• The water vapour they gave out condensed to form oceans.
• Some CO2 dissolved in these oceans

• Green plants and algae evolved an began photosynthesising
• This meant CO2 was being sequestered in the plants as carbon compounds and hydrocarbons.
• It also meant they released a lot of oxygen
• The CO2 they took in remained inside them when they died, and when they became sedimentary layers it remained there.
• When we burn fossil fuels, this CO2 is released.

• The build up of oxygen allowed more complexed organisms to evolve but killed of early ones.
• It also meant the ozone layer (O3) developed and blocked harmful sun rays
• There is virtually no CO2 anymore.