Normally, the percentage of oxygen in air is...

Question 1 / 2707066636eec28f7522a1c51c8e0

Question 1 of 2707066636eec28f7522a1c51c8e0

Normally, the percentage of oxygen in air is __________.

Back

Question 1 of 27070

Q

Normally, the percentage of oxygen in air is __________.

🔍 Key Concepts

• Typical composition of clean, dry atmospheric air at sea level • Relative proportion of oxygen vs. nitrogen in normal air • Difference between normal air and oxygen-enriched or oxygen-depleted atmospheres

💭 Think About

• Think about what percentage of air is nitrogen first, then how much is left for oxygen and other gases. • Consider what is usually meant by a "normal breathable atmosphere" in firefighting and damage control training. • Ask yourself which option sounds like a realistic everyday value, and which options sound like emergency/abnormal conditions.

✅ Before You Answer

• Recall the commonly taught value for oxygen content of normal air in basic first aid or firefighting courses. • Eliminate any options that would indicate dangerously low oxygen where people might lose consciousness. • Eliminate any options that would indicate oxygen-enriched atmospheres, which increase fire and explosion risk.

Question 1 of 27070

Q

Normally, the percentage of oxygen in air is __________.

A

16%

B

18%

C

21%

D

25%

Question 1 / 2707066636eec28f7522a1c51c8e0

Question 1 of 2707066636eec28f7522a1c51c8e0

Normally, the percentage of oxygen in air is __________.

Back

Question 1 of 27070

Q

Normally, the percentage of oxygen in air is __________.

🔍 Key Concepts

• Typical composition of clean, dry atmospheric air at sea level • Relative proportion of oxygen vs. nitrogen in normal air • Difference between normal air and oxygen-enriched or oxygen-depleted atmospheres

💭 Think About

• Think about what percentage of air is nitrogen first, then how much is left for oxygen and other gases. • Consider what is usually meant by a "normal breathable atmosphere" in firefighting and damage control training. • Ask yourself which option sounds like a realistic everyday value, and which options sound like emergency/abnormal conditions.

✅ Before You Answer

• Recall the commonly taught value for oxygen content of normal air in basic first aid or firefighting courses. • Eliminate any options that would indicate dangerously low oxygen where people might lose consciousness. • Eliminate any options that would indicate oxygen-enriched atmospheres, which increase fire and explosion risk.