Air And Atmsophere

Question 1

What was the atmosphere like 4.5 Billion years ago?

Answer 1

The earth was hot and covered in volcanoes which spewed CO2, ammonia, methane, nitrogen and steam into the atmosphere

Question 2

What was the atmosphere like 4 Billion years ago?

Answer 2

The Earth cools and the water vapour condenses to create the oceans. The atmosphere consists of mainly water.

Question 3

What was the atmosphere like 2.5 billion years ago?

Answer 3

Mostly CO2 and nitrogen, but oxygen levels are rising as the first algae and bacteria evolve and begin photosynthesising.

Question 4

What was the atmosphere like 200 million years ago?

Answer 4

Mostly nitrogen and oxygen, as the first respiring animals and plants evolve and this keeps the levels of CO2 and O2 balanced through respiration and photosynthesis.

Question 5

What is the present atmosphere like?

Answer 5

Mainly nitrogen and oxygen, though CO2 and oxygen have been kept in balance through respiration and photosynthesis.

Question 6

What is the composition of gasses in the air?

Answer 6

78% Nitrogen
21% Oxygen
0.9% Argon
0.04% carbon dioxide
0.06% other gasses

Question 7

At what temperature is air liquified?

Answer 7

-200C

Question 8

What is the boiling point of oxygen?

Answer 8

-183C

Question 9

What is the boiling point of nitrogen?

Answer 9

-196C

Question 10

How is air separated through fractional distillation?

Answer 10

Air is cooled to -200C and solid CO2 and water are removed. The liquefied air is fed to the fractionating column which is warmer at the bottom than the top. The oxygen and argon have higher boiling points, so remain liquids and are piped off the bottom of the fractionating column. The temperature at the bottom of the column is higher than the boiling point of nitrogen, so it rises up and is piped off the top as a gas.

Question 11

What is one property and use of nitrogen?

Answer 11

• property: important plant nutrient
• use: to make fertilisers

Question 12

What is one use and property of oxygen?

Answer 12

• property: Reactant in respiration
• use: life support + oxygen for medical reasons

Question 13

What is one property and one use of CO2?

Answer 13

• property: starves fire of oxygen
• use: fire extinguishers

Question 14

What is one use and property of neon?

Answer 14

• Property: glows
• use: neon signs

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Question 15

What is one property and use of helium?

Answer 15

• property: less dense than air
• use: helium balloons

Question 16

What is one property and use of argon?

Answer 16

• property: inert
• use: lightbulbs