Is Oxygen A Pure Substance? (ANSWER With Simple Explanation)

Yes, oxygen is considered a pure substance.

Even though oxygen gas is actually a molecule (rather than a single atom of oxygen as we usually see in elemental pure substances), it still qualifies.

In this article, we’ll explain what a pure substance is, what oxygen (and oxygen gas is), and why it is that oxygen is considered a pure substance.

Why is Oxygen A Pure Substance?

What Is A Pure Substance?

In this question, we are looking at what a “pure substance” is from the angle of science and chemistry.

A substance is considered to be a “pure substance” when it is made up of only one kind of element, or one kind of compound.

A good example of an elemental pure substance is pure silver (any silver alloys are not considered pure substances).

A good example of a pure substance composed of a compound is salt (sodium and chlorine bonded together).

What Is Oxygen? Is Oxygen An Element?

Oxygen in its simplest form is an element.

An element is any material which cannot be broken apart into a simpler substance.

A good example of a substance that is not an element is salt.

Sodium and chlorine are bonded together, and can be broken apart into their separate substances.

Elemental oxygen cannot be broken down or apart into any other simpler substance.

However, it should be noted for the record that oxygen also exists as a gas.

Oxygen gas is actually two oxygen atoms bonded to each other.

Oxygen bonded to oxygen is not considered a compound, even though it involves two atoms bonded to each other.

To be a compound, the two atoms would have to be different substances.

When two atoms of the same element bond to each other, we call the result a molecule, but not a compound.

Is Oxygen Gas An Element?

Strangely enough, yes, oxygen gas (O2), is considered an element.

Oxygen gas (O2) is different than elemental oxygen (just one O).

But since the components of oxygen gas are the same (just oxygen, and nothing else), oxygen gas is still an element.

Is Oxygen (Or Even Oxygen Gas O2) A Pure Substance?

Yes, elemental oxygen and oxygen gas are both considered a pure substance.

The reason is that there is only one kind of atom in the elemental oxygen and in the resulting molecule that is oxygen gas.

Since there are no other kinds of atoms, molecules, compounds, or substances in oxygen or oxygen gas, these substances are both considered pure substances.

Is Oxygen Gas A Compound?

No, oxygen gas (O2) is not considered a compound.

A compound is formed when substances (element, molecule, or compound) bond to other elements, molecules, or compounds.

The key is that the materials that form the compound cannot be the same.

In the case of oxygen (elemental or oxygen gas), the components are just oxygen and nothing else.

Since there is only one kind of atom in this substance, it cannot be considered a compound.

As noted above, oxygen gas is considered a molecule, and also still an element.

Is Oxygen A Mixture?

No, neither elemental oxygen nor oxygen gas (O2) is considered a mixture.

A mixture is a material made up or more than one substance, where the substances are not bonded to each other.

In the case of elemental oxygen, all you have is oxygen atoms.

In the gas of oxygen gas (O2), all you have is oxygen bonded to other oxygen molecules all floating around together.

Since there are no other substances, oxygen is not considered a mixture.

That being said, we think that when many people ask this question, they are thinking more about the air that we breath.

The air that we breath while walking around outside is definitely a mixture.

Air is a mixture of multiple substances that are not bonded to each other, including but not limited to oxygen, nitrogen, boron, carbon dioxide, and more.

But air is not the same as oxygen.

What Type Of Mixture Is Oxygen? Homogeneous Or Heterogeneous?

As discussed right above this paragraph, oxygen is not a mixture. It is a pure substance, in both its elemental and gaseous forms.

We would call it homogeneous, since it is the same throughout the substance.

Air, on the other hand, is a mixture. It can be homogeneous or heterogeneous, depending on the air and the sample size.

The air all around the world is different, as a result of pollution as well as evaporation of water molecules into the air.

Thus when you are answering questions about whether air is heterogeneous or homogeneous, you’ll need to be clear about what kind of air you’ve got, and what’s in it.

Curious about the properties of other familiar substances? Check out our articles about: clear quartz vs diamond, brick, chrysocolla, and amber.