Tag: separation methods

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Multiple choice chemistry separation of matter sedimentation, decantation and filtration other methods of separation separation methods

Sublimation is used to purify:

  1. plasma

  2. gases

  3. solids

  4. liquids
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Sublimation is a technique that helps chemists to purify. During sublimation,upon heating, a solid substance is converted to the gas phase without passing through the liquid phase.  A solid is heated under vacuum. The solid volatilizes and condenses as a purified compound on a cooled surface, a non-volatile residue of impurities is left behind.

Multiple choice chemistry separation of matter sedimentation, decantation and filtration other methods of separation separation methods

Process in which solid is directly converted to vapors state is called:

  1. sublimation

  2. filtration

  3. drying

  4. cooling
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Sublimation is a technique that helps chemists to purify. During sublimation,upon heating, a solid substance is converted to the gas phase without passing through the liquid phase.  A solid is heated under vacuum. The solid volatilizes and condenses as a purified compound on a cooled surface,  a non-volatile residue of impurities is left behind.

Multiple choice chemistry separation of matter sedimentation, decantation and filtration other methods of separation separation methods

Sublimation can be used to separate a mixture of solids in which:

  1. one sublimes other does not

  2. both sublimes

  3. both does not sublime

  4. sublimation cannot be used for separation
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Sublimation can be used to separate a mixture of solids in which one sublimes other does not. Thus, ammonium chloride can be separated from sodium chloride by sublimation. Ammonium chloride sublimes whereas sodium chloride does not.

Multiple choice chemistry separation of matter sedimentation, decantation and filtration other methods of separation separation methods
The combustion of candles, containing paraffin wax, to carbon dioxide and water vapour is sublimation.

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The term sublimation refers to a physical change of state and is not used to describe transformation of a solid to a gas in a chemical reaction. The combustion of candles, containing paraffin wax, to carbon dioxide and water vapor is not sublimation but a chemical reaction with oxygen.

Multiple choice chemistry separation of matter sedimentation, decantation and filtration other methods of separation separation methods

On heating iodine and sand which will sublime?

  1. Sand

  2. Iodine

  3. Both a and b

  4. None of them
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Iodine is a chemical element with atomic number 53. The heaviest of the stable halogens, it exists as a lustrous, purple-black metallic solid at a standard conditions that sublimes readily to form a violet gas.

Multiple choice chemistry separation of matter sedimentation, decantation and filtration other methods of separation separation methods

Sublimation process is used:

  1. to separate mixtures that contain a sublimate with a non-volatile component from a non-sublimate impurity

  2. to separate mixtures that contain a sublimate with a volatile component from a non-sublimate volatile impurity

  3. to separate mixtures that contain a sublimate with a volatile component from a non-sublimate impurity

  4. none of above
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Sublimation process is used to separate mixtures that contain a sublimate with a volatile component from a non-sublimate impurity. Thus, ammonium chloride can be separated from sodium chloride by sublimation. Ammonium chloride sublimes whereas sodium chloride does not.

Multiple choice chemistry separation of matter sedimentation, decantation and filtration other methods of separation separation methods
Method of separation by sublimation is limited. 

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The given statement is True.
 Method of separation by sublimation is limited. This method can be used for separation of only those compounds that sublime (i.e, change their state on heating from solid to vapour without passing through liquid state). Examples of sublimable compounds include iodine, ammonium chloride, camphor and naphthalene.

Note: If in the given mixture, none of the compounds is sublimable, then method of separation by sublimation cannot be used.

Multiple choice chemistry separation of matter sedimentation, decantation and filtration other methods of separation separation methods

Ammonium chloride is separated from a mixture of sodium chloride and ammonium chloride by the process of:

  1. evaporation

  2. sublimation

  3. fractional distillation

  4. filtration
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Ammonium chloride is separated from a mixture of sodium chloride and ammonium chloride by the process of sublimation. Ammonium chloride can be sublimed whereas sodium chloride cannot be sublimed. When a mixture of sodium chloride and ammonium chloride is heated, ammonium chloride changes its state from solid to vapour. The vapours of ammonium chloride are then condensed on cold surface. Sodium chloride is left behind.