Page 1 :
Unit 9, MIX AND SEPARATE, Properties of sugar candy, • Colour : Colourless, • Odour : Odourless, • State : Solid, • Taste : Sweet, If we are breaking a sugar candy repeatedly, we will ultimately get a small, particle invisible to our naked eye, possessing all the properties of sugar., This particle is what we call as a molecule of sugar candy., Molecule, The smallest particle of a substance retaining all the properties of that, substance is known as its molecule. Substances that exist in the solid,, liquid and gaseous states are made up of molecules., Pure substances, If a substance contains only one type of molecules, it is known as a pure, substance. Eg :- Sugar, Water, Salt, Aluminum, Glycerine, Baking soda,, Copper, Potassium permanganate, Oxygen, Silver, Copper sulphate (Blue, vitriol) etc., What molecules will be present in a solution made by dissolving sugar, candy in water?, Molecules of sugar candy and water, Mixture, If there are more than one type of molecules present in a substance, it is, called a mixture., Examine the table given below.

Page 2 :
Analyse the table and classify them into pure substances and mixtures., , Homogeneous Mixture, If a mixture exhibits the same property throughout, that mixture is called, homogeneous mixture. Eg:- Salt solution, , Heterogeneous Mixture, If a mixture exhibits different properties in different parts, that mixture is called, heterogeneous mixture. Eg:- Mixture of chalk powder and water., , Different types of solutions

Page 3 :
All solutions are homogeneous mixtures. Solutions exist in solid, liquid and, gaseous states., Examine the table., , Based on the constituent particles, identify the characteristics of each solution., , •, •, •, •, , Brass - Solid dissolved in solid, Soda – Gas dissolved in liquid, Glycerine dissolved in water – Liquid dissolved in liquid, Air – Different types of gases dissolved each other, Separation of mixtures, We can separate the components of mixtures by using suitable, methods. Decantation, Filtration,Evaporation, Magnetic separation,, winding etc. are some of the methods to separate components, from mixtures., Decantation, Decantation is the process of separating the clear liquid above after, sedimentation of the components of a mixture., Eg:- Separating clear water from a mixture of sand and water., Filtration, Filtration is the process of separating the constituent particles of a, mixture by making use of a sieve., The difference in the size of the particles in the mixture is made use, of in filtering. Filter paper, Tea strainer, cloth piece, sieve etc. are, used for filtration., Eg:-, , •, , Clear water is obtained by filtering water through a filter paper., , •, , Tea dust is removed from tea using a tea strainer

Page 4 :
•, , Mud is filtered from muddy water by filtering it using a piece of, cloth, , • Gravel is separated from sand using sieve, • Mesh with small holes is used to sieve rice powder for making, pathiri., Separation of dissolved components, We can separate dissolved components from a mixture by, evaporation. Evaporation is the process by which a liquid absorbs, heat and gets converted in to vapour. In salt pans, evaporation is used, to separate salt from salt water., Magnetic separation, If iron powder is mixed with other powders, we can separate the iron, powder using a magnet. This is called magnetic separation., Separation using difference in density, A mixture of non-mixing liquids such as water and kerosine etc. can, be separated by making use of the difference in the density. A device, named separating funnel is used for this., Winding, In paddy fields, winding is performed to fly the chaff away from the, rice grains. In kitchen also we use this method to remove the chaff, and stones from the rice. Here the difference in the weight of the, components of the mixture is made use of., Sand as a good sieve, Sand can filter the impurities of water. So usually when the water from the, septic tank reaches the well through the sand or soil, the water will be pure., But if the distance between them is less, the soil can not filter the impurities, completely. So, a distance of at least 15 meters should be maintained, between the well and septic tank., Concept map, Complete the concept map by writing the methods, employed and cite examples.

Page 5 :
Let us assess, 1. Observe the materials given below.

Page 6 :
1. How can you separate the components if A and B get mixed?, We can remove iron from the mixture using a magnet., 2. How can you separate the components if A and C get mixed?, Put the mixture in to water and stir. Salt will dissolve in it. Remove wax, powder by filtration. Regain the salt by evaporation., 3. How can you separate the components if A and D get mixed?, Put the mixture in to water. Wax powder will float and sand will sediment., We can collect the wax powder then by filtration using a tea strainer. The, sand will remain in the pot., 2. Using which equipment will you get water with maximum purity while, filtering muddy water? Why?, a. Cloth, b. Filter paper, c. Tea strainer, Ans. By using filter paper. Because the, holes in the filter paper are more, tiny than cloth and tea strainer., 3. How does pure water differ from sugar solution based on the, constituents present in them?, Pure water contains the molecules of water only. Hence it is a pure, substance. Sugar solution contains molecules of sugar and water. So, it is a, mixture.