Earth's atmosphere (approximate values) | Exit Quiz | Oak National Academy

What is the approximate percentage of oxygen in Earth's atmosphere?

• 80%

• 20%

• 1%

• 0.04%

Answer explanation

The approximate percentage of oxygen in Earth's atmosphere is 20%.

Which is the most abundant gas in Earth's atmosphere?

Answer explanation

The most abundant gas in Earth's atmosphere is nitrogen.

What molecule does the atmosphere contain as a vapour, as well as in the liquid and solid states?

Answer explanation

Water molecules are present in Earth's atmosphere in the gas, liquid and solid state.

Why is it difficult for humans to breathe sufficient oxygen at high altitudes?

• the air pressure increases at high altitudes

• air is more dense at high altitudes

• there are less oxygen molecules per volume of air at high altitudes

Answer explanation

It is difficult for humans to breathe at high altitudes as there are less oxygen molecules per volume of air compared to sea level.

What is the name for very small particles of solids and liquids that are suspended in air?

Answer explanation

Particulates are very small particles of solids and liquids that are suspended in air.

At high altitudes such as the top of Everest, how does the composition of the atmosphere compare to at sea level?

• there is a higher percentage of nitrogen

• there is a lower percentage of oxygen

• the percentage composition of gases is the same

Answer explanation

The percentage composition of gases in the atmosphere is the same at high altitudes such as the top of mountains. The gas particles become less dense as altitude increases.