L2 - The atmosphere is a gas

Question 1

What is the mean radius of the Earth?

Answer 1

6,370 km.

Question 2

What is the mass of the Earth?

Answer 2

6×10 ^24 kg

Question 3

What is the mean density of the Earth?

Answer 3

5.5 x 10^3 kg m-3

Question 4

What percentage of the Earth’s surface is covered by oceans?

Answer 4

71%

Question 5

What is the average depth of the oceans?

Answer 5

4 km

Question 6

How does the mass of the oceans compare to the atmosphere?

Answer 6

It is 300 times the mass of the atmosphere.

Question 7

What is the mean density of the oceans?

Answer 7

10 ^3 kgm-3

Question 8

What is the standard atmospheric temperature range?

Answer 8

273–293 K (0–20°C).

Question 9

What is the standard atmospheric pressure at sea level?

Answer 9

1013.15 mbar or hPa.

Question 10

What is the air density at sea level?

Answer 10

1.2 kg m-3

Question 11

At what height is 90% of the Earth’s atmosphere contained?

Answer 11

below 16 km

Question 12

What is the scale height?

Answer 12

The vertical distance where air density or pressure decreases by a factor of 1/e≈0.368

Question 13

What is the lapse rate in the troposphere?

Answer 13

6.5 K/km

Question 14

Where does the temperature inversion occur in the atmosphere?

Answer 14

at the tropopause

Question 15

What is the temperature at the stratopause?

Answer 15

260 K

Question 16

Where is the coldest place in the atmosphere?

Answer 16

The mesopause (T=170K, height = 80 km).

Question 17

How high does the exosphere extend?

Answer 17

500–1000 km and beyond

Question 18

What influences the planetary boundary layer?

Answer 18

Surface topography, local winds, and weather.

Question 19

What is the turbopause?

Answer 19

The region up to 10 km where atmospheric motion causes mixing, maintaining uniform gas composition

Question 20

What was the primary component of Earth’s primordial atmosphere?

Answer 20

hydrogen

Question 21

What led to the formation of Earth’s oceans?

Answer 21

Water vapor condensed to form clouds and rain, accumulating surface water

Question 22

When did oxygen first start forming?

Answer 22

During the evolutionary atmosphere stage (4.0–3.3 BYA) through photosynthesis and photo-dissociation of water.

Question 23

What process contributed to early oxygen production?

Answer 23

Photosynthesis by cyanobacteria and green plants.

Question 24

When did current oxygen levels reach?

Answer 24

0.3 BYA.

Question 25

Where is the maximum concentration of ozone found?

Answer 25

Between 20–40 km altitude (10–12 ppm)

Question 26

What is the Chapman Mechanism?

Answer 26

A process describing ozone creation and destruction through photolysis of O2

Question 27

Why is the ozone layer critical for life?

Answer 27

It absorbs soft UV radiation (0.2–0.3 microns).

Question 28

When and where does the ozone hole form?

Answer 28

Over Antarctica in early spring (Nov–Dec).

Question 29

What causes the ozone hole?

Answer 29

Chlorine released from manmade CFCs, accelerated by reactions on polar stratospheric clouds (PSCs).

Question 30

What is the Montreal Protocol?

Answer 30

A 1992 treaty banning CFCs, leading to partial ozone recovery.

Question 31

When is the ozone hole expected to fully recover?

Answer 31

By 2053, to pre-CFC emission levels.