Pure Substances and Mixtures

Physicists can categorize matter as solid, liquid, or gas. But there are other ways to classify matter, as well — such as pure substances and mixtures, used by chemists. Cataloguing is one of the elementary procedures in science. All matter can be categorized as either a pure substance or a mixture.


Classification of Matter

Pure Substances:

A pure substance has a fixed and constant structure — like sugar or salt. An unadulterated substance can be one or the other an element or a compound, but the configuration of a pure substance does not vary.

  • Elements

An element is made up of a single kind of atom. An atom is the minutest unit of an element that still holds all the properties of the element. Example: Gold is an element. If you cut and cut a portion of gold until only single minute unit is left that can’t be sliced any more without losing the characteristics that make gold, and then we’ve got an atom.

The atoms of an element all have the same number of protons. Protons are constituent subatomic particles of an atom. Elements are the structural blocks of matter. And they’re characterized and symbolized in a strange table you might have appreciated at one time or another — the periodic table.

  • Compounds

A compound is created out of two or more than two elements in a precise ratio. For instance, water is a compound made up of two elements, hydrogen (H) and oxygen (O). These elements come together in a very specific way — in a proportion of two hydrogen units to one oxygen unit, known as H2O.

Many compounds have hydrogen and oxygen, but only water has that special 2 to 1 ratio we all know. The mixture that is water has physical and chemical properties dissimilar from both hydrogen and oxygen — water’s characteristics are a matchless permutation of the two elements.

The components of a compound can’t be easily separated: Chemists have to rely on some type of chemical reaction.


Mixtures are physical mixtures of pure elements that have no certain or persistent configuration — the arrangement of a mixture differs according to who concocts the mixture.

Although chemists have a tough time sorting out compounds into their exact elements, the different parts of a concoction can be effortlessly divided by physical means, such as filtration.

For instance, assume one has a mixture of salt and sand, and the individual wants to refine the sand by eliminating the salt. This can be done by adding water, dissolving the salt, and then clarifying the mixture. One then ends up with unadulterated sand.

Mixtures are majorly of two types, either homogeneous and heterogeneous:

  • A homogeneous mixture, occasionally called a solution, is comparatively unvarying in configuration; every unit of the mixture is like every other unit.

For instance, if you liquefy sugar in water and blend it really well, your concoction is essentially the same no matter where you sample it.

  • A heterogeneous mixture is a concoction whose configuration varies from spot to spot within the sample.

For instance, if you put a little sugar in a vessel, add some sand, and then shake the jar a couple of times, your concoction doesn’t have the same configuration all throughout the jar. As the sand is heftier, there’s possibly more sand at the bottom of the jar and more sugar at the top.

Practise This Question

Some of the nitrogen travels as inorganic ions, but the bulk of it is carried in the organic form as amino acids and related compounds.