Topic 1 - The Earths's Sea and Atmosphere

Question 1

How did oceans form

Answer 1

The water vapour in the air condensed .

Question 2

How was today’s atmosphere created

Answer 2

1. Volcanoes erupted putting carbon dioxide, water vapour, and small amounts of ammonia, methane, and nitrogen in the atmosphere.
2. CO2 dissolved in oceans
3. Animals used CO2 to make shells
4. Dead animals fell to the sea floor making sedimentary rock
5. Plants photosynthesised

Question 2

Why has the amount of CO2 increased

Answer 2

1. Deforestation
2. Burning fossil fuels
3. Farming

Question 3

What gases are in our atmosphere today?

Answer 3

Nitrogen - 78%
Oxygen - 21%
Argon - 0.9%
CO2 - 0.04%

Question 4

Can we be certain what the early atmosphere was like?

Answer 4

No because no one was there and there are no records

Question 6

How do u test how much oxygen is in the air?

Answer 6

Copper 2 gas syringes
Iron wool in beaker of water

measure the volume of gas in the syringe at the end of experiment (1)
 subtract from {100 cm3 / original volume} to give volume of oxygen (1)

Amount at start -end
————————–x 100
Amount at start

Question 7

What is the balanced equation for copper reacting with oxygen?

Answer 7

2Cu + O2 -> 2CuO

Question 8

What were the 3 stages of the evolution of the atmosphere?

Answer 8

Phase 1 - Volcanoes gave out gas
Phase 2 - Plants evolved and photosynthesised
Phase 3 - Ozone layer allowed evolution of complex animals.

Question 9

How did the ozone layer affect the atmosphere?

Answer 9

There was a build up of oxygen which killed some early organisms but it allowed other complex organisms to evolve.
It also created the ozone layer which blocked harmful rays from the sun.