Tag: elements, compounds and mixtures

Quizzes (19) Questions (57)

Questions Related to elements, compounds and mixtures

Multiple choice separation of components of mixtures methods of separation elements, compounds and mixtures chemistry

Which of the following cannot be used for liquid-liquid separation?

  1. Magnet

  2. Sublimation

  3. Crystallization

  4. All of above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Magnetic separation and sublimation can be used to separate solid from solid. Crystallization is used to recover solid from liquid. Hence, none of the above methods is used for separation of liquid from liquid.

Multiple choice separation of components of mixtures methods of separation elements, compounds and mixtures chemistry

Gaseous diffusion works on the principle that

  1. Molecules of a lighter isotope would pass through a porous barrier more readily than those of a heavier isotope

  2. Molecules of a heavier isotope would pass through a porous barrier more readily than those of a lighter isotope

  3. Heavier and lighter particles will pass readily through the porous barrier

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

Gaseous diffusion works on the principle that molecules of a lighter isotope would pass through a porous barrier more readily than those of a heavier isotope.

Multiple choice separation of components of mixtures methods of separation elements, compounds and mixtures chemistry

______for the removal of VOCs from air, in recent times have become important due to environmental and economic driving forces.

  1. Liqueafaction

  2. Condensation based gas separations

  3. Solubility-based gas separations

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

Solubility-based gas separations for applications such as the removal of VOCs from air, in recent times have become important due to environmental and economic driving forces.The main objective is to obtain membranes that exhibit high permeability and high selectivity for the heavier species over the light gases.

Multiple choice separation of components of mixtures methods of separation elements, compounds and mixtures chemistry

If a steam-jacket eudiometer with $23ml$ of oxygen and $4ml$ of hydrogen are mixed over mercury, determine how much and which gas would be left as uncombined after the mixture is sparked?

  1. $21$mL $O _2$
  2. $3.0$mL $H _2$
  3. $24$mL $O _2$
  4. $28$mL $O _2$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

$\displaystyle  2H _2 + O _2 \rightarrow 2H _2O$
2 moles of hydrogen will react with 1 mole of oxygen.
Volume is directly proportional to the number of moles.
4 ml of hydrogen will react with $\displaystyle  \dfrac {4 \times 1}{2}= 2$  ml of oxygen.
$\displaystyle  23-2 = 21 ml$  of oxygen will be left uncombined.

Multiple choice separation of components of mixtures methods of separation elements, compounds and mixtures chemistry

If a steam-jacket eudiometer with 23ml of oxygen and 4ml of hydrogen are mixed over mercury, determine the total volume in ml of the gas after the mixture was sparked?

  1. $16$
  2. $25$
  3. $34$
  4. $36$
  5. $40$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

$\displaystyle  2H _2 + O _2 \rightarrow 2H _2O$
2 moles of hydrogen will react with 1 mole of oxygen to form 2 moles of water.
Volume is directly proportional to the number of moles.
4 ml of hydrogen will react with $\displaystyle  \dfrac {4 \times 1}{2}= 2$  ml of oxygen to form 4 ml of water.
$\displaystyle  23-2 = 21 ml$  of oxygen will be left uncombined.
Thus, after the mixture was sparked, 21 ml oxygen and 4 ml water are present.
Total volume of the gas after the mixture was sparked $\displaystyle  = 21 + 4 = 25 $ ml.

Multiple choice separation of components of mixtures methods of separation elements, compounds and mixtures chemistry

_______is a technology used to produce enriched uranium by forcing gaseous uranium hexafluoride through semipermeable membranes.

  1. Gas solubility

  2. Gas condensation

  3. Solidification

  4. Gas diffusion
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Gaseous diffusion is a technology used to produce enriched uranium by forcing gaseous uranium hexafluoride through semipermeable membranes. This produces a slight separation between the molecules containing uranium-235 and uranium-238. By use of a large cascade of many stages, high separations can be achieved. 

Multiple choice separation of components of mixtures methods of separation elements, compounds and mixtures chemistry

A technique in which two liquids are separated by heating process is known as :

  1. distillation

  2. filtration

  3. evaporation

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

Distillation is a process of separating the component or substances from a liquid mixture by selective evaporation and condensation. Distillation may result in essentially complete separation (nearly pure components), or it may be a partial separation that increases the concentration of selected components of the mixture.

Multiple choice separation of components of mixtures methods of separation elements, compounds and mixtures chemistry

A cheque was suspected to be forged. Which technique could be used to compare the various pigments in the different inks?

  1. Chromatography

  2. Evaporation

  3. Crystallisation

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

A cheque was suspected to be forged. Chromatography could be used to compare the various pigments in the different inks.  Here, different inks will have different affinity for  stationary phase  and solvent (mobile phase).