Tag: chemistry

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Questions Related to chemistry

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

Which of the following is commonly used for removing the water layer from a system containing oil and water?

  1. Thermometer

  2. Separatory funnel

  3. Fiame spectrophotometer

  4. Burette

  5. Volumetric flask
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Water and oil are immiscible and they form two separate layer, oil have less density than water, so it floats on the water surface so, the water and oil layer can easily be separated by the separatory funnel.

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

Which statement explains why oxygen can be separated from nitrogen by the fractional distillation of liquid air?

  1. Oxygen is more dense than nitrogen

  2. Oxygen is more reactive than nitrogen

  3. The two elements have different boiling points

  4. The two gases are in different groups of the Periodic Table
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Fractional distillation is a process of separation of mixtures based on the difference in their boiling points.

so, oxygen and nitrogen can be separated by fractional distillation because they have different boiling points.

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

Which of the following processes enable pure water to be obtained from seawater?
I filtration
II distillation
III evaporation

  1. I and II only

  2. I and III only

  3. II and III only

  4. I,II and III
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Distillation and evaporation enables pure water to obtained from seawater,

both these process includes the evaporation of water and then condensing the water vapours to obtain pure form of water.

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

During distillation, some porcelain chips are added to the mixture being distilled to ______________.

  1. make the distilling flask more stable

  2. purify the mixture

  3. raise the temperature

  4. make the boiling smoother
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Procelain chips are added to the mixture for two reasons: to prevent the superheating of liquid and to make the distilling flask more stable.

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

Due to difference in degree of adsorption of gases by charcoal, a mixture of noble gases can be separated by adsorption on:

  1. burnt charcoal

  2. coconut charcoal

  3. powdered charcoal

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

Due to difference in degree of adsorption of gases by charcoal, a mixture of noble gases can be separated by adsorption double walled tube containing coconut charcoal.

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

Which of the following statements are true with respect to the effect of solubility with temperature?

  1. Solubility of gas in liquid increases with temperature

  2. Solubility of gas in liquid decreases with temperature

  3. Solubility of solute in solution increases with temperature

  4. Solubility of solute in solution decreases with temperature
Reveal answer Fill a bubble to check yourself
B,C Correct answer
Explanation

Due to the increase in kinetic energy at higher temperature, the solvent milecules effectively break the solute molecules that are held together by intermolecular forces.

Therefore, solubility of solute in solution increases with temperature.
Also, the higher kinetic energy causes more motion in the gas molecules which break intermolecular bonds & escape from solution.
Therefore, solubility of gas decreases with temperature.

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

The volume of water that would convert $10\ ml$ of decamolar $HCl$ solution to decamolar solutions is 

  1. $10^{3}\ ml$
  2. $10^{2}\ ml$
  3. $9.9\times 10^{3}\ ml$
  4. $1.2\ L$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
Milli moles of conc.HCl=milli moles of dil HCl
10×10=V×11010×10=V×110⇒V=1000ml⇒V=1000ml
Thus 990ml of water should be added to 10ml on conc.HCl to get decinormal solution.
Hence (a) is the correct answer.
Multiple choice separation of components of mixtures methods of separation elements, compounds and mixtures chemistry

An azeotropic mixture cannot be separated into its components by fractional distillation.

  1. True

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

An azeotropic mixture cannot be separated into its components by fractional distillation because, when an azeotrope is boiled, the vapor has the same proportions of constituents as the unboiled mixture. The statement is true