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Name : ________________

Subject :__________________

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Quote :

SCIENCE CLASS 6 CHAPTER 5 SEPARATION OF SUBSTANCES

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WHY DO WE NEED TO SEPARATE SUBSTANCES

  • We need to separate different components of a mixture to:
  • 1.Separate or remove impurities.
  • A)To remove stones from grains or pulses.
  • B)Remove husk from grains
  • 2.Separate 2 different but useful components
  • A)Cream from milk
  • B)Mixture of orange and guava
  • 3.Separate useful and non useful components
  • A)Tea leaves from tea
  • B)Pulp from juice

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METHODS OF SEPARATION

  • HANDPICKING
  • THRESHING
  • WINNOWING
  • SIEVING
  • SEDIMENTATION/DECANTATION
  • FILTRATION
  • EVAPORATION/CONDENSATION

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EXPLANATION:

Handpicking- The process of separating solid particles from a mixture by hand is called handpicking. Eg: Separating stones from rice.

Threshing- The process of separating grains from stalks by beating them on a hard surface is called threshing. Eg: Separating wheat grains from stalks.

Winnowing-The process of separating lighter and heavier particles by using wind or blowing air is called winnowing. It is used to separate heavier wheat grains from lighter husk particles.

Sieving-The process of separating very fine particles from a bigger one by using a sieve is called sieving. It is used to separate bran from flour and pebbles from sand at construction site..

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Sedimentation/Decantation-When we allow the mixture to stand for a while, the sand settles down. This process is called sedimentation. When we carefully pour out water, this process is called decantation.

Filtration-Filtration is a process by which insoluble solids can be removed froma liquid by using a filter paper. Evaporation- The process of conversion of water into vapour form on heating is called evaporation.

Condensation- The process of conversion of water vapour into liquid form is called condensation.

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SATURATED SOlUTION

  • The solution that has maximum amount of dissolved solute in it and cannot dissolve further amount of solute at that temperature is called saturated solution.
  • solubility is increased on heating as the space between water molecules increases.
  • cooling decreases the solubility.