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1. 1.

   Name the process used for the separation of the following.

   1. Stones and pebbles from sand
   2. Stones from rice
   3. Bran from wheat flour
   4. Chaff from grain
   S A M P L E

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   Answer:

   S A M P L E

   1. Sieving
   2. Handpicking
   3. Sieving
   4. Winnwoing
2. 2.

   Write T for the true statement and F for the false one. Correct the false statement(s).

   1. The solid particles that settle down during sedimentation are called supernatant.
   2. A mixture of sand and water can be separated by sedimentation only.
   3. Filtration is done to remove pulp from fresh fruit juice.
   4. Salt is obtained from sea water by condensation.
   5. The substance that dissolves is called the solvent.
   6. The solubility of a solute cannot be increased by stirring.
   S A M P L E

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   Answer:

   S A M P L E

   1. False The solid particles that settle down during sedimentat...
   2. False A mixture of sand and water cannot be separated by sedimentation...
   3. ...
   4. ...
   5. ...
   6. ...
3. 3.

   Choose the correct option.

   1. Grains or seeds are separated from the stalk by
      1. hand-picking
      2. winnowing
      3. sieving
      4. threshing
   2. Winnowing is used to separate the grain from the
      1. solvent
      2. sediment
      3. stalk
      4. chaff
   3. Hand-picking is preferred when
      1. the quantity of the mixture is small
      2. the unwanted substance is present in large quantities
      3. the unwanted substance can dissolve
      4. the size or colour of the unwanted substance is the same as the useful one
   4. Condensation takes place only when
      1. water vapour hits a cold surface
      2. water vapour hits a hot surface
      3. a hot surface hits a warm surface
      4. water is heated
   5. Which of the following is soluble in water?
      1. Chalk
      2. Sugar
      3. Sand
      4. Wood
   S A M P L E

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   Answer:

   S A M P L E

   1. (d) threshing
   2. (d) chaff
   3. (a) the quantity of the mixture is sma
   4. (a) water vapour hits a cold surfa...
   5. ...
4. 4.

   Fill in the blanks with the correct words.

   1. The particles of the insoluble solid should be ___________ (bigger/smaller) than the holes in the filtering device.
   2. Chalk and sand are ___________ (soluble/insoluble) in water.
   3. The substance in which the solute dissolves is called a ___________ (solution/solvent).
   4. The quantity of a substance that can dissolve in ___________ (hot/cold) water is much more as compared to ___________ (hot/cold) water.
   5. Sugar in the ___________ (powdered/solid) form dissolves first.
5. 5.

   Name the different methods of separation.

6. 6.

   When can sieving be done?