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CBSE-IX-Science

06: 1-Is Matter around Us Pure

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  • #
    Science Is Matter around Us Pure part 1
  • #
    Section : I
  • Qstn #1
    What is meant by a substance?
    Ans : Substance can be defined as that kind of matter where constituent particles cannot be separated from each other by any physical process since they are all similar in chemical properties.
  • Qstn #2
    List the points of differences between homogeneous and heterogeneous mixtures.
    Ans :
  • #
    Section : II
  • Qstn #1
    Differentiate between homogeneous and heterogeneous mixtures with examples.
    Ans :
  • Qstn #2
    How are sol, solution and suspension different from each other?
    Ans :
  • Qstn #3
    To make a saturated solution, 36 g of sodium chloride is dissolved in 100 g of water at 293 K. Find its concentration at this temperature.
    Ans : Mass of sodium chloride (solute) = 36 g

    Mass of water (solvent) = 100 g

    Mass of solution = 36 + 100 = 136 g

    Therefore, concentration percentage = mass of solute/mass of solution

    = 26.47 %
  • #
    Section : III
  • Qstn #1
    How will you separate a mixture containing kerosene and petrol (difference in their boiling points is more than), which are miscible with each other?
    Ans : We can separate a mixture containing kerosene and petrol by distillation technique since difference in their boiling points is more than. So through distillation we can get them separated.
  • Qstn #2
    Name the technique to separate
  • Qstn #2-i
    butter from curd,
    Ans : centrifugation method.
  • Qstn #2-ii
    salt from sea-water,
    Ans : evaporation method.
  • Qstn #3
    What type of mixtures are separated by the technique of crystallisation?
    Ans : From impure samples of solids, pure solid crystals can be obtained by the method of crystallization for eg to obtain pure sugar from impure sample of the same.
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