The key difference between hydrogen and oxygen is that the hydrogen is a very light gas whereas the oxygen is a heavy gas.
We are all aware of the importance of oxygen gas to all life forms, especially human beings. It is one gas that supports all life forms. There is another gas, which we call as hydrogen that is equally important for us. There are many differences between hydrogen and oxygen. But, the greatest benefit to us is in the chemistry between these two gases as it results in formation of water that is a necessity for us. Let us compare the two gases on the basis of their properties.
What is Hydrogen?
Hydrogen is the most abundant material on earth, taking up nearly 75% of the mass of all matter. We can classify hydrogen gas as a diatomic gas because it has two hydrogen atoms. As it is very light, this gas is rare in earth’s atmosphere because it escapes the gravity of earth. Most of the hydrogen on the earth is in the form of elemental hydrogen. The vast majority is in the form of hydrocarbons and water.
The molar mass of the hydrogen gas molecule is 2.016 g/mol. It is a colourless, odourless, tasteless and highly flammable gas. This gas forms as a product of some types of anaerobic metabolism reactions and also some microorganisms can produce this gas. However, the first production of hydrogen gas was recorded at early 16th century via the reaction between metals and acids. Later, scientists found that this gas forms water when burnt in the air which leads to name this gas as hydrogen (meaning “water-former”). In modern technology, we produce this gas in industrial scale via steam reforming natural gas or in laboratories via electrolysis of water.
Besides, there are two major applications of this gas;. That is; in fossil fuel processing (in hydrocracking) and in ammonia production during the fertilizer production. Furthermore, there are some concerns regarding the hydrogen gas since it can cause embrittlement of metals which can alter the designs of metal-containing structures such as pipelines. This gas is not much reactive under standard conditions, but it can form compounds with most elements such as highly electronegative elements, i.e. halogens.
What is Oxygen?
Oxygen is the third most abundant element in the atmosphere, after hydrogen, and helium. It constitutes about 50% of Earth’s mass and makes up almost 90% of the world’s oceans. In the atmosphere of earth, oxygen takes up 21% of volume and 23% by weight. Also, oxygen gas molecule has two atoms of Oxygen. Hence, it is a diatomic gas. The molar mass of this gas is 31.998 g/mol. Moreover, this gaseous form is the most stable form of elemental oxygen.
Besides, during the process of photosynthesis, organisms such as cyanobacteria, algae and plants produce oxygen gas as a byproduct. This produced oxygen is important for the respiration of other living organisms. It is a colourless, odourless and tasteless gas. It is noncombustible, but it actively supports the combustion of other materials.
What are the Similarities Between Hydrogen and Oxygen?
- Both hydrogen and oxygen are gaseous compounds at standard conditions.
- Also, both are diatomic molecules in nature.
- Furthermore, both are abundant in the earth’s atmosphere.
- Moreover, they are both reactive gases, and their reaction produces water which is essential for our survival.
What is the Difference Between Hydrogen and Oxygen?
Hydrogen is the most abundant material on earth, taking up nearly 75% of the mass of all matter whereas oxygen is the third most abundant element in the atmosphere, after hydrogen, and helium. Both these gases occur in their gaseous state at standard temperature and pressure conditions. However, hydrogen gas is rare in our atmosphere because it escapes the gravity due to its lightweight. In contrast, oxygen is abundant in our atmosphere; about 12% of air is oxygen. Therefore, the abundance is one difference between hydrogen and oxygen. Furthermore, another difference between hydrogen and oxygen is that the hydrogen gas is highly flammable while oxygen gas is non-flammable. But, oxygen gas aids the combustion of other materials.
Aboveall, the key difference between hydrogen and oxygen is that the hydrogen is a very light gas whereas the oxygen is a heavy gas. Moreover, further differences are shown in the infographic of the difference between hydrogen and oxygen.
Summary – Hydrogen vs Oxygen
Hydrogen and oxygen chemical elements occur in their gaseous state as diatomic molecules at the standard pressure and temperature conditions. The key difference between hydrogen and oxygen is that the hydrogen is a very light gas whereas the oxygen is a heavy gas.
1. “Oxygen.” National Center for Biotechnology Information. PubChem Compound Database, U.S. National Library of Medicine. Available here
2. “Hydrogen.” National Center for Biotechnology Information. PubChem Compound Database, U.S. National Library of Medicine. Available here