Topic outline

    • Sorting Materials Into Groups

      Q30. What are miscible liquids?

      Ans. The liquids which dissolve in water are called miscible liquids. Example: vinegar, alcohol, milk, etc.


      Q31. What are immiscible liquids?

      Ans. The liquids which do not dissolve in water are called immiscible liquids. Example: kerosene oil, coconut oil, petrol, diesel, ether etc.


      Q32. What is diffusion?

      Ans. Diffusion is the tendency of molecules to spread out in order to occupy an available space.


      Q33. Why do we need to group materials?

      Ans. We group materials to study their properties and also to observe any patterns in them. Grouping of material saves our time, energy and makes our work easier.

      Q34. How does a chemist give us the required medicine quickly?

      Ans. All related medicines are kept together on a proper place after sorting. This sorting of medicines in a chemist shop makes it easy for the chemist to give us the required medicine quickly.


      Q35. What are lustrous materials?

      Ans. The materials which have natural shine on their surface or the shine appears when they are freshly cut or sand papered are called lustrous materials. Generally most of the metals are lustrous.


      Q36. Classify the following things as transparent, opaque and translucent things. marble, computer, plastic sheet, wood, water, frosted glass, butter paper, air, glass door






      frosted glass



      butter paper

      glass door

      plastic sheet






      iron sheet





      Q37. Differentiate between naturally occurring materials and man-made materials?


      Naturally occurring materials

      Man-made materials

      1. The materials which occur in nature are called naturally occurring materials.

      1. The materials which do not occur in nature but are made by man by combining two or more materials are called man-made materials.


      2. Examples – wood, cotton, stone soil etc.

      2. Examples – plastic, glass, detergent, steel etc.



      Q38. Define soluble substance, insoluble substance and solubility.

      Ans. The substance which dissolves in water is called soluble substance. Example – milk, ink, sugar, common salt etc.

      The substance which do not dissolves in water is called insoluble substance. Example – sand, stone, mud, glass etc.

      The property of substance due to which it dissolves in water is called solubility.

      Q39. Find odd one out from the following:

            a.   stone, bed, cup , boy, wooden box

            b.   mango, cherry, rose, grapes, apple

            c.   gold, soil, aluminum, silver, platinum, iron

            d.   sugar, salt, ink, lemon juice, milk, wood


            a.   boy (all others are non-living)

            b.   rose (all others are fruit)

            c.   soil (all others are metals)

            d.   wood (all others are soluble in water)


      Q40. Think and write few bases on which we can group objects.

      Ans. We can group object on the following bases:

                              i.        Material used such as wood, metal, plastic etc.

                             ii.        Material is soft or hard.

                            iii.        Material is soluble or insoluble in water.

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