Difference between a pure substance and a mixture
Pure substance vs a mixture:
Everything on this planet, be it at home, on the road, at the beach, in the countryside belongs to either one of these two categories. Every element that is around us are made up of either a single element or a mixture of several elements. Therefore, it is of extreme importance that one recognizes the difference between a pure substance and a mixture.
What is a pure substance?
A pure substance is usually made up of the same kind of atoms or molecules and there is only one kind of matter present and only one kind of particles present in a pure substance. It may require chemical analysis in order to determine if an element is pure as there exists no other ways to determine this fact. Usually, the constituent atoms of a pure substance would be chemically bonded that they can not be separated by physical means and carry a constant composition with fixed ratios of elements.
Some examples of pure substances can be pure gold, coal, which is is made up of nothing but carbon atoms, salt which only has NaCl and etc.
What is a mixture?
A misxture can be defined as a combination of two or more substances which are not chemically united and do not exist in fixed proportions to each other. While most natural substances are mixtures, it is indeed easy to distinguish a mixture at a glance as the different components which make up a mixture is often visible to the naked eye.
Some examples for mixture can be sand, air, which is made up of several gases, bronze which is a mixture of tin and copper and steel which is an alloy of different metals put together.
What is the difference between a pure substance and a mixture?
While several pure substances can be mixed together to form a mixture, a mixture can be separated in to pure substances as well. Yet, a mixture’s individual properties are known to retain their original forms and no new chemical if formed as result of the combining whereas a pure substance may easily mingle with each other and can be hard to purify them afterwards.
The components of a mixture can often be seen to the naked eye. Also, these components can easily be separated physically as well. And yet, the molecules or the atoms of a pure substance cannot be seen by the naked eye. Also, separating the atoms or molecules of a pure substance cannot be done physically. It often requires a chemical procedure to do so. For example, whereas in a mixture of different pebbles or sea sand mixed with water, one can easily distinguish the different components with the naked eye. Its also very easy to separate the elements which exist in the mixture and can be done so physically. And yet, identifying the different molecules or chemical bonds in salt is impossible with the naked eye. It is also impossible to separate whatever elements which make it up without putting the substance under a chemical treatment to do so.
Whereas mixtures usually present a changing of physical properties, physical properties of a pure substance such as the boiling point or melting point of pure substances usually remain unchanging. For example, pure water boils at 100 degrees C and a mixture of alcohol and water boils over a range of temperatures.