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ASSIGNMENT CLASS VII CHAP 3, Part – II Elements , compounds and ( Separation Techniques of )

Mixture can be separated into its constituent by various method. Seperation technique totally depend upon the nature of the constituent.

Q1. Describe a method to separate solid to solid mixture . Ans . We can separate solid to solid mixture by using Method , when one of the component is soluble. In this method we use a appropriate solvent to dissolve one of the component of the mixture .After that we filter the solute .The soluble solute get filtered from the insoluble solid. The filtered solution can be further separated from the solvent by heating or keeping in the sun.In this way we can separate out the two mixture.

Q2. Differentiate between Solute and Solvent. Ans Solute Solvent The solid that is dissolved or spread evenly in the The in which solute is dissolved is called solvent is called Solute . solvent. e.g. In syrup sugar is the solute. e.g. In sugar syrup is the solvent

Q3. Name the various method used to separate solid to liquid mixture. Ans. The solid to liquid mixtures can be separated by various method – i. ii. iii. Distillation Q4. What do you mean by filtration ? Draw a well labelled diagram to show filtration. Give one example too. Ans. Filtration is the simplest method to separate mixture when it contain one insoluble solid component and a liquid component by using a filter paper. The clear liquid that passes through the filterpaper is called Filtrate . E.g. Such mixtures are Chalk and water, silver chloride and water.

Q5. Differentiate between Residue and Filtrate . Ans . Residue Filtrate The solid left behind on the filter paper after The clear liquid that passes through the filter paper filtration is called Residue. after filtration is called Filtrate. e.g. In the mixture of chalk and water chalk is the e.g. In the mixture of chalk and water water is the residue filtrate.

Q6. State any two advantages oof filtration. Ans. The two advantages of Filtration are as follows- i.The component of the mixture are completely separated . ii. It takes very little time for separation.

Q7. Define evaporation. State any one limitation of Evaporation Ans . The process of change of liquid state into vapour state below its boling point by absorption of heat is called Evaporation. e.g. Sodium chloride and Water , Magnesium Sulphate and Water can be seperateed by this method. Limitation : There is loss of liquid component while evaporating the mixture.

Q8.What do you know about Distillation with a well labelled diagram? Give example too. Ans . The conversion of liquid into vapours and condensing the vapours back into liquid is known as Distillation. This method is used for separation of liquid containing a non volatile solid component dissolved in it. E.g. Iodine and Methyl , Iodine and chlorophyll can be separated by this method.

Q9. List the method used to separate Liquid to liquid mixture. Ans. The liquid to liquid mixture can be separated on the basis of following physical properties – Method Physical properties used for Example separation 1. Using Seperating funnel i. Immiscibility of the two mixture di sulphide and water ii. Difference in the densities of two 2. i. Two liquids dissolved in one a. Ethyl alcohol and water another b. Methyl alcohol and Acetone ii. Difference in their points.

Q10. Draw a well labelled diagram of the Seperating funnel.

Q11. What do you mean by Fractional Distillation ? State any one limitation of it. Ans. The method used to separate the two miscible liquids in small fractions having differing by 10o to 20o C is called Fractional Distillation. E.g. Mixture of Ethyl alcohol and water. , Mixture of Acetone and Water can be separated by it. Limitation : Liquid forming constant boiling mixture cannot be separated.

Q12. What do you mean by ? List any two ways it is useful to us . Ans. The process of separating different dissolved components of the mixture by different of the component over an appropriate adsorbing material is called Chromatography. It is useful for : i. Isolation of compounds from natural sources . ii. Seperation , purification and identification of the constituent of the mixture.

Q13. State any two advantages of using Chromatography. Ans. The two advantages of the chromatography are – i. Only a small quantity of the sample needed. ii. The components are not consumed during the separation.

WORKSHEET Q1. Fill up the blanks – i. Distillation involves two process ______and ______. ii. The most reliable technique of separating coloured substance is ______. iii. The process of conversion of liquid state to vapoou state below its boiling point is called _____. iv. When the distillate is collected in fraction at different boiling point is called ______. v. The mixture of two or more metal or a non metal is called _____. Ans. i. Vopourisation , ii. Chromatography iii. Evaporation iv. Fractional distillation v. Alloy

Q2. Differentiate between the following – i. Evaporation and Sublimation ii. Distillation and Fractional Distillation iii. Solute and Solvent iv. Filtrate and Residue v. Vopourisation and Condensation

Q3. Name the method to separate the following mixtures - i. Sea water -Evaporation ii. Sand and Salt- Using Solvent method iii. Alcohol and Water- Fractional distillation iv.Kerosene and Water- Using Seperating funnel v. products –Fractional distillation vi. Colored pigment from green ink. – Chromatography vii. Red ink from red and blue ink mixture .- Chromatography

Q4. Answer the following with respect to the diagram given below- i. Name and label the following setup. Ans. The following setup shows the method of Fractional Distillation. ii. Name the used in the given setup.What is the purpose of using it. Ans . Leibig’s Condensor. It is a type of Water Condensor used to cool the vapour into liquid . iii. State any one limitation of this method. iv. Name the two process used in this technique of separation. Ans. Liquids forming constant boiling mixture cannot be separated by this method.