Chemistry - Is Matter Around Us Pure



  • A pure substance is that that consists of single type of particle or particles.

  • Mixtures of two or more pure components without any undesirable substance are known as Mixtures, for example, water, minerals, soil etc.

  • A homogeneous mixture of two or more substances is known as solution. For example, lemonade, soda water etc.

  • Solution could be in any form such as – it could be in liquid, solid, or gaseous.

  • Alloys are another example of mixture that contain homogeneous mixtures of metals; they cannot be separated into their components by physical methods. E.g. For example, brass is a mixture of zinc (approximately 30%) and copper (about 70%).

Significant Features of Solution

  • Solution is normally a homogeneous mixture.

  • The particles of a solution are even smaller than 1 nm (10-9 meter) in diameter and hence, these are not visible from the naked eyes.

  • The path of light is not visible in a solution.

  • The dissolved particles cannot be separated from the mixture by the simple process of filtration.

  • The dissolved particles do not settle down when it left undisturbed.

  • At a given temperature, when no more solute can be dissolved in a solution, it is known as ‘saturated solution.’

  • At a given temperature, the amount of the dissolved particles present in the saturated solution, is known as solubility.’


  • A suspension is a heterogeneous mixture in which the solute particles do not dissolve, but rather remain suspended throughout the bulk of the medium, is known as ‘suspension.’

Significant features of Suspension

  • Particles of a suspension are clearly visible from the naked eye.

Suspended Particles
  • The particles of a suspension scatter a beam of light that passes through it and likewise, its path is visible.

  • The salute particles can be separated from the mixture by the simple process of filtration.


  • A heterogeneous mixture is known as ‘colloid.’ E.g. mist, fog, smoke, face cream, etc.

  • The size of colloid particles is too small to see from the naked eye.

  • Colloid particles are big enough to scatter a beam of light passing through it and make the path visible.

  • Colloid particles cannot be separated from the mixture by the simple process of filtration.

  • The special filtration technique i.e. centrifugation, can be used to separate the colloidal particles.


  • The process of separation of components of a mixture is called as chromatography; normally it is used for the color separation.

  • Chromatography technique is used for separation of those solutes that dissolve in the same solvent.


  • The process of purifying a liquid by heating and cooling means is known as distillation.


  • The process that separates a pure solid in the form of its crystals from a solution is known as ‘crystallization.’


  • In 1661, Robert Boyle was the first scientist who used the term element; Antoine Laurent Lavoisier, a French chemist, was the first who experimentally define the term element.

  • Element is as a basic form of matter that cannot be broken down into simpler substances by a chemical reaction.

  • Elements normally can be categorized as metals, non-metals, and metalloids.


  • A solid material, which typically is hard, ductile, malleable, shiny, and fusible with good electrical and thermal conductivity, is known as metal. E.g. gold, silver, copper, aluminum, etc.

  • Mercury is the only metal that remains liquid at room temperature.


  • All elements or substances, which are not metals, are known as non-metals. E.g. hydrogen, oxygen, iodine, carbon, etc.

  • Non-metals have variety of colors and they are poor conductors of heat and electricity.

  • Non-metals are not lustrous, sonorous, or malleable.


  • A substance, composed of two or more elements, is known as ‘compound.’

  • Compound is the result of the chemically combination of two or more elements in a fixed proportion.

  • Properties of a compound are somehow different from its constituent elements, whereas, the properties of a mixture are the same as of its constituting elements or compounds.