Introduction
Anything which occupies space is known as matter. Air is known for its inevitable behaviour in our life. As our earth is surrounded by a blanket of air in different layers called the atmosphere. There are so many elements which are responsible for the existence of life, but among all of them, air is considered as most important, as no organism can survive without air even for a second. The major role of air is in the breathing process, along with that air is an abiotic component of the environment like other abiotic component examples: wind, rain, climate, soil, etc.
Composition of Gases:
Air is made up of various gases in different compositions. Various gases present in the atmosphere are argon, nitrogen, carbon dioxide in different proportions and some gases also present in very small amounts like argon, water vapour and other gases. Air also has various microorganisms in a very small amount like bacteria, spores along with that dust particle are also there.
Nature of Gases:
We cannot see air, i.e. they are in invisible form and they are free to flow everywhere as they exist in a gaseous state. Because of all these properties of gases, it is also known as states of matter. As it has weight, compressible in nature and also takes space to occupy. Properties of gases are studied under different physical and chemical conditions.
Chemical Composition of Air:
Mixtures of various gases in different compositions are termed as air, and air is present on the earth's atmosphere. Air is mainly colourless in nature and also odourless i.e. you can’t feel gas. It atmosphere gases are present in different composition i.e. Nitrogen 78%; oxygen 21% and in the remaining 1% different gases and water vapour are present. Amount of water vapour varies from place to place as the arid region has less moisture percent than a wetland. As the moisture carrying capacity depends majorly on temperature. Composition of air does not mainly but if you are at highest then it will change.
Some other component of air is:
Some other components of air are mentioned below:
Sulfur dioxide(SO2)
Methane(CH4 )
Nitrous oxide(N2O)
Ozone(O3)
Nitrogen dioxide(NO2)
Iodine(I2)
Carbon Monooxide(CO)
Ammonia(NH3)
Properties of Gases:
As gases are one form of matter like other matter. There are different properties which are present in the air. Some of the important properties are discussed below:
1. Colourless and odourless: Air is colourless and odourless as it can't be seen by eyes. We can only feel the air. All organisms need air for breathing for their survival.
2. Occupy space: Like other matter, air also occupies space. For example: on blowing a balloon expands as air is being filled inside the balloon.
3. Air exerts pressure: As air has weight and because of that air is exerted as it has a weight which is commonly known as air pressure. Mixtures of gases are mainly denser near high altitudes as gravity rule is also applied on air. This is the reason behind the lesser density of air in the mountainous areas.
4. Expansion: Another famous property of gas is its expanding property. On heating, it expands and occupies more space. As the expanding thickness of air decreases.
Gases We Breathe:
The air which we inhale and exhale is not pure oxygen or carbon dioxide, it's a mixture of gas. We all are familiar with the fact that our body is made up of different cells and all these cells require oxygen for their survival and for performing day to day functioning. So for all these functions, it must respire by which supply of oxygen occurs throughout the cells. When we inhale we require oxygen and when we exhale we give out carbon dioxide.
Composition of Gases We Inhale:
Our earth surface is surrounded by an atmosphere which is a mixture of various gases like 78% nitrogen, 21% oxygen, 1% argon, 0.04% carbon dioxide; 0.5% water vapour. During the process of inhalation, we inhale the same mixture of air from the nose. When respiration occurs we take the same composition of air which is already there in the atmosphere. Example: when organisms are underwater they breathe air having more quantity oxygen or helium.
Composition of Gases We Exhale:
During the exhalation process, we breathe out almost the same air, which we inhale. One thing which changes during the exhalation and inhalation process is the percentage of oxygen and carbon dioxide. As during the inhalation process percentage of oxygen is 21% and of carbon dioxide is 0.04% we take in. Whereas during the exhalation process, we exhale out 16.4% of oxygen and 4.4% percentage of carbon dioxide. This change is because our cells require more oxygen to produce energy for various metabolic processes to occur and carbon dioxide comes out as a byproduct.
FAQs on Composition Gases Breathe
1. What is the approximate composition of the air we inhale?
The air we inhale is a mixture of several gases. While the exact composition can vary slightly, it is generally made up of:
- Nitrogen (N₂): Approximately 78%
- Oxygen (O₂): Approximately 21%
- Argon (Ar): Approximately 0.93%
- Carbon Dioxide (CO₂): Approximately 0.04%
It also contains trace amounts of other gases like neon and helium, along with variable amounts of water vapour.
2. How does the composition of exhaled air differ from the air we inhale?
The composition changes significantly due to the process of gas exchange in our lungs. Compared to inhaled air, the air we exhale contains:
- Less Oxygen: The percentage of oxygen drops to about 16% because it is absorbed into the bloodstream.
- More Carbon Dioxide: The percentage of carbon dioxide increases significantly to about 4% as it is a waste product removed from the blood.
- More Water Vapour: Exhaled air is saturated with water.
The percentage of nitrogen remains almost the same as it is not used by the body during respiration.
3. Why do we exhale more carbon dioxide than we inhale?
We exhale more carbon dioxide because it is a waste product of cellular respiration. This is the metabolic process where our body's cells use the oxygen we breathe to break down glucose (sugar from food) to produce energy. This essential reaction releases carbon dioxide and water. The blood then carries this waste carbon dioxide from the cells to the lungs to be expelled from the body through exhalation.
4. What is the biological importance of oxygen in the air we breathe?
Oxygen is fundamentally important for survival because it is the key reactant in cellular respiration. This process allows our cells to generate ATP (adenosine triphosphate), the primary energy currency of the cell. Without a continuous supply of oxygen, our cells cannot produce enough energy to perform their functions, which would quickly lead to tissue and organ failure.
5. If nitrogen is the most abundant gas we inhale (78%), why can't our bodies use it directly from the air?
Although we are surrounded by nitrogen, our bodies cannot use it in its gaseous form (N₂). The two nitrogen atoms in a molecule are held together by a very strong triple bond, making the gas chemically inert or unreactive. Our lungs and blood do not have the biological tools (enzymes) to break this bond and absorb the nitrogen. Instead, we get the nitrogen we need for building proteins and DNA by eating plants or other animals, which have absorbed it from the soil in different, usable chemical forms.
6. What happens to inert gases like argon and helium when we breathe them in?
Inert gases like argon, neon, and helium do not have a biological role in respiration. When we inhale them as part of the air, they travel into our lungs along with oxygen and nitrogen. However, because they are chemically unreactive, they do not get absorbed into the bloodstream through the alveoli. They are simply pushed out of the lungs, unchanged, during exhalation.
7. What is the main difference between respiration and breathing?
While often used interchangeably, breathing and respiration are different processes. Breathing (or ventilation) is the physical act of moving air in and out of the lungs. In contrast, respiration is the chemical process that occurs inside the cells, where oxygen is used to produce energy from food, releasing carbon dioxide as a byproduct. Breathing makes cellular respiration possible by supplying the necessary oxygen and removing the waste carbon dioxide.
