L2: The Changing Atmosphere Flashcards
What is needed to melt or boil a substance?
To melt or boil a substance, we need to overcome the forces/attractions between the particles.
What is the result of high inter molecular forces?
High melting an boiling point
Which are stronger: chemical bonds or inter molecular forces?
Chemical bonds are much stronger than intermolecular forces
What are the percentages of the gases in our atmosphere?
Nitrogen (N2): 78%
Oxygen (O2): 21%
Water vapour (H2O): 0-4%
Argon (Ar): 1%
Carbon dioxide (CO2): 0.03%
What forces do we need to overcome when boiling or melting a substance?
The forces/attraction between the particles. The greater the forces between particles, the higher the melting or boiling point.
What were the gases of the early athmosphere?
Carbon dioxide, water vapour, nitrogen, methane (CH4) and ammonia (NH3)
Why was the presence of carbon dioxide so high?
Because of the high amount of volcanic activity
How did the oceans form?
The water vapour condensed to form water aka the oceans
What dissolved in the oceans?
Carbon dioxide
What formed after the dissolvement of carbon dioxide in oceans?
Carbon percipitates and sediment on the sea bed
When did the next change begin?
2.7 billion years ago
What began to appear?
Algae
What evolved from algae over the following billion years?
Green plants
Why did plants appear?
Because they are able to photosynthesise, the reactants of which are carbon dioxide and water
What are the products of photosynthesis?
Glucose and oxygen
