Tag: separation methods

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Questions Related to separation methods

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

The salt can be easily obtained from the salty water by the process of

  1. Evaporation

  2. Chromatography

  3. Crystallization

  4. Both a and b
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The process of conversion of water into vapour by heating it to its boiling point is called evaporation.The salt can be easily obtained from the salty water by the process of evaporation. If we boil this water, the water evaporates completely, leaving behind only the salt.

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

 Sublimation is a technique that helps chemists to:

  1. break

  2. purify

  3. melt

  4. freeze
Reveal answer Fill a bubble to check yourself
B 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 requires additional energy and is an:

  1. endothermic change

  2. exothermic change

  3. both a and b

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

Sublimation is the process of transferring molecules in the solid phase to the gaseous phase. Since liquid state is skipped in this process, a large amount of energy has to be supplied in order to provide the required molecular motion to the molecules. Hence it is an endothermic change

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

Statement I: Evaporation is an endothermic process.
Statement II: Heat is absorbed as a substance cools.

  1. Both Statement I and Statement II are correct and Statement II is the correct explanation of Statement I.

  2. Both Statement I and Statement II are correct, but Statement II is not the correct explanation of Statement I.

  3. Statement I is correct, but Statement II is incorrect.

  4. Statement I is incorrect, but Statement II is correct.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Option C is the correct answer.

Evaporation is an endothermic process. Because, evaporation requires heat. When heat is given into the system, evaporation from the system occurs.
When a substance cools down, it gives off heat in its surrounding. Thus, heat is not absorbed, rather heat is given out into the surrounding for the substance to cool.

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

Sublimation is the process of separating a liquid from its solution by evaporating it and then condensing its vapour.

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
The answer is $false$.

Sublimation is the process by which a solid directly converts into gas without undergoing liquid state or vice versa. 
For example, naphthalene.
Multiple choice chemistry separation of matter sedimentation, decantation and filtration other methods of separation separation methods

A $40\ ml$ of a mixture of ${ H } _{ 2 }$ and ${ O } _{ 2 }$ at $18\ ^0C$ and $1\ atm$ pressure was parked so that the for water was complete. The remaining pure gas had a volume of $10\ ml$ at 18 $^0C$ and $1\ atm$ pressure, the remaining gas was ${ H } _{ 2,}$ the mole fraction of ${ H } _{ 2 }$ in the $40\ ml$ mixture is:

  1. $0.75$
  2. $0.5$
  3. $0.65$
  4. $0.85$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

In the reaction 2H2 + O2 → 2H2O, if 10 ml of H2 remains after complete water formation, then 30 ml of gas reacted. This 30 ml consists of H2 and O2 in 2:1 ratio, so 20 ml H2 + 10 ml O2 reacted. Initial H2 = 20 ml (reacted) + 10 ml (remaining) = 30 ml. Mole fraction = 30/40 = 0.75. The remaining gas is H2, confirming H2 was in excess.