Earth & Atmosphere

Question 1

What was Earths early atmosphere thought to have contained

Answer 1

Little or no oxygen
Large amount of CO2
Water vapour
Small amounts of other gases

Question 2

How did the condensation of water vapour form oceans

Answer 2

As the Earth cooled water vapour condensed and fell as rain to form the seas and oceans

Question 3

How was the amount of carbon dioxide in the early atmosphere decreased 

Answer 3

Dissolved in the oceans and marine organisms used it to make calcium carbonate for their shells

Question 4

How did the growth of primitive plants gradually increase the amount of oxygen in the early atmosphere

Answer 4

Forms of life began to evolve in the oceans due to the dissolved co2 and photosynthesis began
oxygen was then built up in the oceans and then the atmosphere

Question 5

Describe the chemical test for oxygen

Answer 5

Glowing splint relights in the presence of oxygen