Science Gill(g) Ludhiana

Methods of separating the substances 1.Sublimation 2.Winnowing 3.Distillation 4.Sieving 5.Filtration 6.Crystallisation 7.Centrifugation 8.Separation by separating funnel 9.Magnetic separation

1.Sublimation:-

Certain substances when heated, pass directly from the solid to the vapour state without melting. The vapours when cooled give back, the solid substance. This process is known as sublimation. It is used in separating a volatile solid from a non-volatile solid.

2.Winnowing:- It’s the process of separating heavy and lighter particles from a mixture by throwing the mixture from a height. The blowing wind takes away the lighter particles to some distance and the heavier particles due to their weight fall straight down to the earth. The heavier particles are collected at a nearer place and the lighter particles are collected at a distant place.

3.Distillation:-It is the process of converting a liquid into vapours,then condensing the vapours and collecting the liquid . It is used for separating a liquid from a non-volatile substance. Common salt and water can be separated by this method.

4.Sieving:-In this process the smaller and the bigger particles from a mixture are separated with the help of a sieve. The smaller particles pass down through the sieve and bigger particles remain on the sieve eg.sieving the flour or tea

5.Filteration:This method is used to remove suspended particles by using filter paper . This process is based on the fact that the solvent particles can pass through the filter paper, while the suspended particles can not. As a result suspended particles are retained on the filter paper.

6.Crystallisation:-It is the most common method for the purification of solid substances. it is based on the fact that substances are more soluble in a hot solvent than in the cold. On cooling the hot saturated solution, a part of the dissolved substance will separate out from the solution in the form of a solid having definite geometrical pattern.

7.Centrifugation:-It is the process of separating suspended particles from liquid. In this the heavy particles settle down at the bottom of the container and the liquid becomes clear. Better results can be taken by revolving the container with the help of a revolving machine called centrifugal machine. Mixer used in the kitchen is the example of such machine.

8.Separation by separating funnel:-In this process two invisible liquids can be separated with the help of a separating funnel. e.g. mixture of water and oil can be separated with the help of separating funnel. When we put the mixture in the separating funnel, oil being lighter makes a separate layer over water. Lower layer of water can be collected by opening the tap of the separating funnel.

9.Magnetic separation:This process is used to separate the contents of a mixture in which one content is a magnetic substance. In this the magnetic substance is separated with the help of magnet. This process is commonly used in the industries.

1.What is winnowing? Where is it used? 2.Is it possible to separate sugar mixed with wheat floor? If yes, how will you do it? 3.What is sieving? 4.What is the process of converting liquid into

• Text book of class 6th PSEB • Systematic Modern Chemistry by Y.R. Sharma K.L. Chugh M.S. Garkhel Beant Singh www.google.com

We are thankful to Miss Daljit Kaur for her great and timely help in completion of this project.