Difference Between Pure Substance and Mixture

Solid, liquid, and gas are the three fundamental states of matter. However, you can classify the matter in pure substances and mixtures as well. Substances that have a particular composition get called as pure substances. They cannot get separated into other forms of matter. Elements and compounds are the two categories to classify pure substances further. When two or more pure substances come together, we call it a mixture. Mixtures can get divided into two kinds, namely, homogeneous and heterogeneous mixtures. In this article, you will learn about the difference between pure substance and mixture and fundamental concepts of the same.  

Pure Substances and Mixtures

Before we dive into the pure substance vs substance comparison, you must know some essential concepts. It’s important to understand what pure substance is, what is a mixture? and how do they get classified further? 


So as you know, all the substances can get divided into two categories – pure substance and mixture. Here, we will study both categories. 

1 – Pure substance

 The substances that contain only one type of particle and they are free from any mixture, are known as pure substances. Gold, silver, iron, and aluminium are pure substances, to name a few. By their chemical composition, pure substances get divided into two types – elements and compounds.    

  • Elements – An element is a pure substance which contains a single kind of atom. Such a substance cannot get broken into two or a simpler substance by physical or chemical means. For instance, when you can break down gold, what you get is gold again. Elements can be metals, non-metals, and metalloids. 

  • Compounds – Compound is a pure substance; it contains two or more elements which get chemically combined in a predetermined proportion. For example, water is a compound as it has two elements hydrogen and oxygen, which get combined in a fixed proportion.   

2 – Mixture 

Mixtures refer to substances that contain two or more forms of matter. A solution of salt and water, sugar and water, air, different gases, etc. is examples of mixtures. Based on their compositions, mixtures can get divided into two types – homogeneous and heterogeneous mixtures. 

  • Homogeneous Mixtures – Those mixtures having a uniform composition throughout their bodies are homogeneous mixtures. Soda water, lemonade, a mixture of salt in water are a few examples of homogeneous mixtures.  

  • Heterogeneous Mixtures – Those mixtures which do not have a uniform composition entirely are heterogeneous mixtures. A mixture of oil and water, soil and sand are heterogeneous mixtures as they don’t have a uniform composition. 

Difference Between Pure Substance and Mixture

Property

Pure Substance

Mixture

Definition

The substances composed of only one particular matter are pure.

When two or more forms of matter come together to form a substance, it becomes a mixture.

Categories 

Based on their composition, pure substances get classified into elements and compounds.

Based on their composition, mixtures get divided into the homogeneous and heterogeneous mixture. 

Physical properties 

Physical properties of pure substances are definite and constant.

Mixtures have varying physical properties. 

Chemical properties 

Chemical properties of pure substances are constant and definite too.

Mixtures have variable or indefinite chemical properties. 

Purity 

Pure substances are, of course, pure. 

Mixtures are impure substances. 

Separation 

It is not possible to separate pure substances. 

It is possible to separate mixtures by evaporation, magnetic separation, etc. 

Examples 

Gold, oxygen, iron, water

Oil and water, sand and soil, sugar solution

  

FAQ (Frequently Asked Questions)

1. What is a compound?

A compound refers to a matter consisting of two or more different elements joined together chemically. You must know that a molecule forms when two or more atoms or elements get bonded chemically. Those elements might belong to the same type or different ones. For instance, O2 is a diatomic molecule because it has two oxygen molecules which come together chemically. But, CO2 is a compound because it has two different atoms. It has carbon and oxygen which got bonded chemically. 

2. Define the types of mixtures

There are two major categories of mixtures, depending on their composition. One is a homogeneous mixture, and another one is a heterogeneous mixture. 

  • Homogeneous mixture: These mixtures are the ones having uniform composition throughout their body. Salt and water, sugar and water, soda water, lemonade, and air are some of the examples of homogeneous mixtures.  

  • Heterogeneous mixture: These mixtures don’t have uniform composition throughout their body. Mixtures of soil and sand, oil and water, sulfur and iron filings etc. are examples of heterogeneous mixtures.