Difference Between Pure Substance and Mixture

Main Difference

Everything in this world that occupies space is defined as the matter. The matter can be further split into two main categories, pure substance or mixture. A pure substance is made up of same kinds of molecules, elements and compounds are the basic examples of such matter, whereas mixture is made up of two different kinds of molecules, homogeneous mixtures, and heterogeneous mixtures are the major types of mixtures. Pure Substance as the name refers exists in the purest form possible, it has no impurities within it and has the same composition and properties throughout, and on the other hand, the mixture is the combination of two or more different molecules, and each of its constituents tries to retain its identity on them. Moreover, the mixtures are formed without any chemical reaction between the substances; therefore they can be split into constituents using physical or chemical methods.

Comparison Chart

Pure SubstanceMixture
DefinitionA pure substance is made up of the same kind of molecules.The mixture is made up of two different molecules.
Properties & CompositionThe pure substances possess similar properties and composition throughout.In mixtures, properties and composition vary as the constituents are mixed in indefinite proportion.
ImpuritiesA pure substance is in the purest form and has no impurities in it.The mixture has impurities or is made up of two or more than substances.
Melting & Boiling PointPure Substances have sharp melting and boiling point and have standard melting or boiling point.Boiling and melting points of mixtures vary in accordance with the proportion of constituents.
ExampleWater is an example of pure substance.Salt mixed in water is an example of a mixture.

What is Pure Substance?

Pure substances are the type of matter that are formed with the same kind of molecules. They have sharp melting and boiling point as they exist in the purest form. To determine whether the substance is pure or not, the chemical method of checking purity is applied. The pure substances possess similar properties and composition throughout. As they are in their purest form, they can not be split into different components even by using the chemical or physical processes. The pure water is one the basic example of a pure substance, although this water becomes mixture sooner as the impurities or other substances get mixed in it.

What is Mixture?

A mixture is the combination of two or more pure substance in such a way that they are not chemically united. The each pure substance getting into make the mixture have an influence on the mixture as it shows on the type of properties. For instance, with making a mixture of sugar and water, the solution made will be sweet in taste due to the presence of sugar, which has the property of sweetness. When the mixtures are made, they can mainly be of two types; homogeneous mixture and heterogeneous mixture. The homogeneous mixture is the combination of two or more pure substance in such a uniform manner that each of the substance is indistinguishable from the other substance. On the other hand, the pure substances in the heterogeneous mixtures are not uniformly distributed and it results in the formation of non-uniform composition.

Pure Substance vs. Mixture

  • A pure substance is made up of the same kind of molecules, whereas mixture is made up of two different molecules.
  • The pure substances possess similar properties and composition throughout, on the other hand, in mixtures, properties and composition vary as the constituents are mixed in indefinite proportion.
  • A pure substance is in the purest form and has no impurities in it while mixture has impurities or is made up of two or more than substances.
  • Pure Substances have sharp melting and boiling point and have standard melting or boiling point, contrary to this, boiling and melting points of mixtures varies by the proportion of constituents.
  • Water is an example of a pure substance, on the other hand, salt mixed in water is an example of a mixture.

Comparison Video

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Harlon Moss

Harlon currently works as a quality moderator and content writer for Difference Wiki. He graduated from the University of California in 2010 with a degree in Computer Science. Follow him on Twitter @HarlonMoss

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