Lesson 2

Question 1

What is the name of the thin layer of the earth that we live on?

Answer 1

The atmosphere

The atmosphere is a layer of gases surrounding the Earth’s crust.

Question 2

What is the primary gas that makes up about 78% of the Earth’s atmosphere?

Answer 2

Nitrogen

Nitrogen is essential in amino acids and proteins but is unreactive.

Question 3

What percentage of the atmosphere is made up of oxygen?

Answer 3

21%

Oxygen is essential for aerobic respiration and generated through photosynthesis.

Question 4

What is the role of carbon dioxide in the Earth’s atmosphere?

Answer 4

Regulating temperature

Carbon dioxide, though only 0.04% of the atmosphere, plays a crucial role in temperature regulation.

Question 5

What is gas A, which makes up most of the atmosphere?

Answer 5

Nitrogen

Nitrogen is the most abundant gas in the atmosphere.

Question 6

What is the molecular formula for oxygen?

Answer 6

O2

Oxygen exists as a diatomic molecule.

Question 7

What is gas C, which makes up around 1% of the Earth’s atmosphere?

Answer 7

Argon

Argon is a noble gas and is unreactive.

Question 8

Which gas do humans inhale but is not used in the respiration process?

Answer 8

Nitrogen

Nitrogen is inhaled but not utilized in metabolic processes.

Question 9

What two gases make up about 99% of the Earth’s atmosphere?

Answer 9

Nitrogen and Oxygen

Together, these gases dominate the atmospheric composition.

Question 10

Fill in the blank: The atmosphere was formed around ______ billion years ago.

Answer 10

4.6

This marks the beginning of Earth’s atmospheric history.

Question 11

What biological process is the source of oxygen in the atmosphere?

Answer 11

Photosynthesis

Photosynthesis is the process by which plants generate oxygen.

Question 12

True or False: Argon has changed in amount since the Earth was first formed.

Answer 12

False

Argon levels have remained constant since the Earth’s formation.

Question 13

What is the chemical formula for carbon dioxide?

Answer 13

CO2

Carbon dioxide consists of one carbon atom and two oxygen atoms.

Question 14

What percentage of the atmosphere is made up of carbon dioxide?

Answer 14

0.04%

Despite its low percentage, carbon dioxide significantly affects the climate.

Question 15

What is the state change from a solid to a liquid called?

Answer 15

Melting

This process occurs when a solid is heated to its melting point.

Question 16

How does the temperature change as you move towards the center of the Earth?

Answer 16

It increases

Temperature rises due to geothermal gradients within the Earth’s layers.