METHODS OF SEPARATION (PART:- 2)

                                                Activity–2
AIM : Some common materials that are to be separated and their purpose to separate.

In Column 1 of Table, are given a few processes of separation. The purpose of separation and the way separated components are used is mentioned in Column 2 and 3 respectively. However, the information given in Columns 2 and 3 is jumbled up. So we have to match the separation process with purpose and the separated components.

Now the table in which separation process, purpose of separation and separated components are matched is given below :    

(v) Sedimentation, Decantation and Filtration :
Sometimes, it may not be possible to separate components of a mixture by winnowing and handpicking. For example, there may be lighter impurities like dust or soil particles in rice or pulses.
Rice or pulses are usually washed before cooking. When you add water to these, the impurities like dust and soil particles get separated. These impurities go into water, which becomes a little muddy.
When the heavier component in a mixture settles after water is added to it, the process is called sedimentation. When the water (along with the dust) is removed, the process is called decantation.

The same principle is used for separating a mixture of two liquids that do not mix with each other. For example, oil and water from their mixture can be separated by this process. If a mixture of such liquids is allowed to stand for some time, they form two separate layers. The component that forms the top layer can then be separated by decantation.
A mixture of insoluble solid and liquid can be separated by the process of filtration. 

If water is muddy, impurities can be separated by a filter that has even smaller pores. A filter paper is one such filter that has very fine pores 

Separating two components of a mixture by sedimentation and decantation

The figure shows the steps involved in using a filter paper. A filter paper folded in the form of a cone is fixed onto a funnel. The mixture is then poured on the filter paper. Solid particles in the mixture do not pass through it and remain on the filter.

Fruit and vegetable juices are usually filtered before drinking to separate the seeds and solid particles of pulp.