6th Class Science Separation and Substances Separation of Substances

Separation of Substances

Category : 6th Class

Separation of Substances

 

Synopsis

 

 

 

  • Matter can be broadly divided into two major groups "pure?? and "impure"

 

  • Matter is made up of tiny particles called molecules. Molecules are further made of same or different kinds of atoms.

 

  • Molecules of a substance have all the properties of that substance.

 

  •  A pure substance is made up of only one type Of molecules and so it is called homogeneous substance, e.g., elements, compounds.

 

  • An impure substance is made up of more than one type of molecules and it is called heterogeneous substance, e.g., mixtures.

 

  •  A substance which is uniform in its composition and properties throughout is called a homogeneous substance.

 

  •  A substance which is not uniform in its composition and properties throughout is called a heterogeneous substance.

 

  • Methods of Separation: Some simple methods of separating substances that are mixed together are given below.         

 

  •  Handpicking is used for separating slightly larger sized impurities like the pieces of dirt stones and husk from wheat, rice or pulses.

 

  • Threshing is used to separate grain from stalks.

 

  • Winnowing is used to separate heavier and lighter components of a mixture by wind or by blowing air. 

      

  • Sieving makes the fine flour particles to pass through the holes of the sieve while the bidder impurities remain on the sieve.

 

  • Sedimentation settles the heavier component in a mixture after water is added to it.

 

  • Filtration is used to separate components of a mixture of an insoluble solid and a liquid.

 

  • Evaporation is the process of conversion of water into its vapour.

 

  • Condensation is the process of conversion of water vapour into its liquid form.

 

  • Saturated solution is the one in which no more of a substance can be dissolved.

 

  • Sometimes, a combination of methods are to be used to separate mixtures of more than two substances.

 

  • Substances may need to be separated from each other to remove impurities or to get two or more useful products.

 

Methods of separation

           

Type of mixtures  

Methods of separation

(i) Solid-solid (heterogeneous)     

Handpicking, winnowing, sieving, sublimation, magnetic separation

(ii)  Solid-liquid (heterogeneous)

Filtration, sedimentation, decantation

(iii) Solid-liquid (homogeneous)     

Evaporation, distillation, crystallisation

(iv) Liquid-liquid (heterogeneous)   

Decantation, separating funnel

(v)   Liquid-liquid (homogeneous)    

Distillation, liquefaction, fractional distillation

 

Notes - Separation of Substances
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