Section 21: Chemistry of the Atmosphere 1

Question 1

What is the approximate proportion of nitrogen in Earth’s current atmosphere?

Answer 1

80%

Question 2

What is the approximate proportion of oxygen in Earth’s current atmosphere?

Answer 2

20%

Question 3

Which gases are in small proportions in the current atmosphere?

Answer 3

Noble gases, water vapour, carbon dioxide

Question 4

When Earth was formed, which planets was its atmosphere similar to?

Answer 4

Venus and Mars

Question 5

What do Mars and Venus’s atmospheres comprise of?

Answer 5

Carbon dioxide with little or no oxygen

Question 6

What produced the gases present in the Earth’s early atmosphere?

Answer 6

Volcanoes

Question 7

Which gases were present in Earth’s early atmosphere?

Answer 7

Carbon dioxide, water vapour and nitrogen with small amounts of methane and ammonia

Question 8

Why have theories about Earth’s early atmosphere developed and changed over time?

Answer 8

Evidence is limited and it was billions of years ago

Question 9

By what process do algae and plants produce oxygen?

Answer 9

Photosynthesis

Question 10

Write the word equation to represent photosynthesis

Answer 10

Carbon dioxide + water → oxygen + glucose

Question 11

How did the world’s oceans form?

Answer 11

The Earth’s temperature cooled, causing water vapour in the air to condense

Question 12

How did the oceans reduce atmospheric levels of carbon dioxide in Earth’s early atmosphere?

Answer 12

Carbon dioxide dissolved in the oceans