Percentage of Oxygen in air: Overview, Questions, Preparation

The physical properties of oxygen are as follows:

The oxygen atom exists in a diatonic state. Hence, the molecular structure is as follows:

About 49.3% of Earth’s crust is made up of oxygen. It is found in the atmosphere, the land as well as in the oceans. It’s one of the oceans’ essential components and makes up 88.9% of the ocean’s total mass.

It is also abundantly present in the earth’s atmosphere. Our atmosphere consists of nitrogen, hydrogen, oxygen, carbon dioxide, and water vapour.

Out of these, the percentage of oxygen present in the air is almost 21%. 

Plants are responsible for the release of oxygen in the air through photosynthesis. This release of oxygen is counterbalanced by the release of carbon dioxide by humans, animals, etc.

Oxygen is used for a variety of purposes. Some of them are as follows:

• Humans and animals breathe oxygen and exhale carbon dioxide to survive
• Oxygen is required for the combustion of various fuels
• Oxygen pressure reduces as we go to higher elevations. To provide a steady flow of oxygen to their bodies, mountaineers carry tanks with compressed oxygen
• Broken hydrocarbons are heated using oxygen. This combusts them to release water and CO2. This reaction may also release hydrocarbons like acetylene, propylene, and ethylene
• Oxygen helps us to manufacture glass products and for mining purposes
• It helps in the conversion of carbon to carbon dioxide gas. This carbon dioxide is used for the reduction of iron oxides and in various other industries
• It sterilises surfaces by killing anaerobic bacteria that cannot survive in the presence of gas
• It is used in the manufacturing of rockets and missiles as an oxidising agent

Oxygen in Classes 11 and 12

In Class 11, the chapter ‘p-block elements’ discusses the various elements present in groups 13 to 18 of the Periodic Table. Their valence shell electronic configuration and basic reactions are also present in this chapter.

In Class 12, the chapter ‘p-block elements’ discusses the properties, preparation, and uses of oxygen and other elements. ‘P-block elements’ carries a weightage of 8-10 marks in the exams. Hence, one or two questions on oxygen and its compounds may be asked.

Q. How much does the percentage of oxygen drop while flying?

Q. What is the minimum percentage of oxygen in the air required for survival?

Q. How much percentage of oxygen is exhaled in the air by human beings?

Q. What are the different components of air?

Q. Does oxygen dissolve better in freshwater than seawater?

Q. What is the freezing point of oxygen in the air?