C1 Revision: Clean Air

·         The air is a mixture of gases.

·         In the atmosphere, there is:

®     78% Nitrogen

®     21% Oxygen

®     0.9% Argon

®     0.03% Carbon Dioxide

®     Varied amount of water vapour

The early Earth’s atmosphere:

®     Earth was formed about 4.5 billion years ago and its early atmosphere was probably formed from the gases given out by volcanoes.

®     There was intense volcanic activity for the first billions years of the Earth’s existence.

®     Atmosphere was majority carbon dioxide and no oxygen. There were smaller amounts of water vapour, ammonia and methane.

®     As the Earth cooled down, most of the water vapour condensed…