Differences Between Compounds and Mixtures

It is necessary to understand what is meant by the terms 'mixture' and 'compound', in order to differentiate between the two. This article helps by providing a table of comparison for the same.
Did You Know?
Some mixtures like alloys and intermetallic compounds are said to closely resemble pure compounds, in some of their properties, thus causing a confusion about what to classify them as.

Chemistry is the science of matter and one of the principal ways in which matter is classified is according to its composition, which includes the categorization of substances as compounds or mixtures.

What are Compounds?
Compounds refer to substances that are made up of two or more elements that are chemically bonded together. Furthermore, they are pure substances and not mixtures.

Example: Common salt (NaCl)
Sodium is a highly reactive element. It reacts with chlorine which is a yellow-green poisonous gas. They combine to form sodium chloride or common salt.

What are Mixtures?
Mixtures are made up of two or more materials that are not chemically bonded or that do not undergo any chemical reaction. Furthermore, they are mixed physically and are impure substances.

Example: Ocean water
It is a mixture of water and salts. It can be called a water solution which contains several salts.

Mixtures can be divided into two types, namely homogeneous and heterogeneous. Homogeneous mixtures are those which are uniform in composition and properties throughout. Mixtures of this type are also referred to as a true solutions. A sugar solution is an example of homogeneous mixtures. Heterogeneous mixtures are those that are not uniform in composition or those that contain different substances. For example, soil is a combination of many different substances, is non-uniform in composition, and thus, a heterogeneous mixture. Suspensions, colloids, and alloys are other examples of this type.

Differences Between Compounds and Mixtures

Compounds
Mixtures

Compounds are substances that are made up of two or more elements that are chemically combined in fixed proportions.
Mixtures are made up of two or more substances that are not chemically combined. They can be mixed in any proportion.

Compounds have a definite chemical composition.
The composition of a mixture is variable.

The constituents of compounds cannot be identified visually and lose their individual identities.
The constituents of mixtures can be identified visually and do not lose their individual identities.

The elements that compounds are made up of, are combined chemically and cannot be easily separated. They can only be separated by chemical methods.
The substances that mixtures are made up of, are mixed physically and can be separated easily by physical methods like filtration, distillation, etc.

Compounds are pure substances.
Mixtures are impure substances.

They are said to have fixed properties.
They do not have fixed properties. The properties of mixtures depend on the nature and combination ratios of its constituents.

Since it is chemically combined, a new substance is formed. Due to this, a compound may have properties different from its components.
Since, it does not undergo any chemical reaction, no new substance is formed. Due to this, the properties of a mixture and its components remain the same.

Some examples of compounds are Salt (NaCl), Hydrogen Peroxide (H2O2), Baking Soda (NaHCO3), Methane (CH4), etc.
Some examples of mixtures are air (combination of oxygen, nitrogen, and other gases), ocean water (combination of water and salts), oil and water, brass (alloy of zinc and copper), etc.


Considering the aforementioned points, it is understood that compounds and mixtures have many differences and knowing these plays an essential role in further applications or studies related to them.