The key difference between oxygen and air is that oxygen is an individual gaseous component that exists as a part of air whereas air is a mixture of several gases.
Air or atmosphere is a main component of the Earth, other than water (hydrosphere) and soil (lithosphere). Four and a half billion years ago, when the earth was forming, the atmosphere consisted of gases like hydrogen, nitrogen, carbon dioxide, water vapour, hydrogen sulfide, ammonia and methane only. There was no oxygen in the atmosphere. The first living organisms evolved around 3.5 billion years ago, and they did not depend on oxygen for their energy production. Later, photosynthetic organisms evolved, and they started releasing oxygen to the atmosphere as a by-product of photosynthesis. As a result of increasing oxygen in the atmosphere, organisms adapted to utilize oxygen.
CONTENTS
1. Overview and Key Difference
2. What is Oxygen
3. What is Air
4. Side by Side Comparison – Oxygen vs Air in Tabular Form
5. Summary
What is Oxygen?
Oxygen is the element with the atomic number 8, which is present in group 16 of the periodic table. It has three isotopes, 16O, 17O, 18O. Among these 16O is the most stable and abundant isotope. Furthermore, an oxygen atom has eight electrons, and it can obtain two more electrons from another atom to form a -2 charged anion. Alternatively, two oxygen atoms can share four electrons to form a diatomic molecule (O2) to be stable. We call it oxygen gas, as a common term, because this molecule exists in a gas state at standard temperature and pressure. The molecular weight of O2 is 32 g mole-1.
Figure 01: Oxygen Molecule in a Ball and Stick Model
Similarly, we name the three atomic form of oxygen as ozone which is another common form of oxygen. Molecular oxygen is a colourless, odourless gas. There is about 21% of oxygen in the earth’ atmosphere. It is poorly soluble in water and is slightly heavier than air. Oxygen reacts with all the elements to form oxides except inert gases. Therefore, it is a good oxidizing agent. However, this gas is essential in respiration of living organisms and also for the combustion. Oxygen is useful in hospitals, welding, and in many other industries.
What is Air?
Air is a collection of various gases in different quantities, water vapour, and particulate matter. Nitrogen (78%), oxygen (21%), argon (0.9%) and carbon dioxide (0.03%) gases make up to 99.99 % of the air. Other gases like neon, helium, krypton, sulfur dioxide, hydrogen, methane and ammonia are only present in minute concentrations and therefore, known as trace gases. Air is important for climate patterns, and to absorb harmful solar energy, sound wave propagation, etc. Moreover, depending on the composition of air, it may have a colour or odour, but naturally, air is colourless and odourless. If there are more particulate matters, for example, where a factory fume emits, air may have a dark colour and an odour of chemicals.
Figure 02: An Air Balloon in Air
Air pollution is the deterioration of the quality of air by releasing substances or energy in such quantities, which prevent the smooth/ balanced functioning of natural processes and produce undesirable environmental and health effects. Mainly, air pollutants include sulfur dioxide, nitrogen oxides, carbon monoxide, hydrocarbons, particulate matter, CFC, carbon dioxide and ozone. These substances emit due to human activities, and it has resulted in some global problems now.
What is the Difference Between Oxygen and Air?
Air is the mixture of gases in the atmosphere. oxygen is an essential component in air. Therefore, the key difference between oxygen and air is that oxygen is an individual gaseous component that exists as a part of air whereas air is a mixture of several gases. Furthermore, molecular oxygen contains diatomic oxygen molecules while air consists of a mixture of Nitrogen, oxygen, argon and carbon dioxide along with some other trace substances. In brief, oxygen is important in hospitals, welding, and in many other industries whereas air is important for the climate patterns, and to absorb harmful solar energy, sound wave propagation, etc.
Summary – Oxygen vs Air
We study about air in the atmospheric chemistry, a major branch of chemistry. Accordingly, oxygen is an essential component in the air that we need to keep the life on Earth. The key difference between oxygen and air is that oxygen is an individual gaseous component that exists as a part of air whereas air is a mixture of several gases.
Reference:
1. Helmenstine, Anne Marie, Ph.D. “The Chemical Composition of Air.” ThoughtCo, Sep. 21, 2018. Available here
2. “Atmospheric Chemistry.” Wikipedia, Wikimedia Foundation, 8 Nov. 2018. Available here
Image Courtesy:
1.”Oxygen molecule”By Ulflund – Own work, (CC0) via Commons Wikimedia
2.”163235″ by Pixabay (CC0) via pexels