Chemistry

Separation of Mixtures part 2

Alfred Ajibola - Wed, 26th June, 2019 @ 06:15: AM

Topics in Chemistry

Salts and Types of Salt in Chemistry Mixtures and Separation of Mixtures Separation of Mixtures part 2 Separation of Mixtures part 3 Physical Change, Chemical Change, Element, Compound and Mixture Electrolysis, Electrolyte, Electrode, Anode and Cathode Grahams law of diffusion Physical Properties of Metals Daltons Atomic Theory and its Modifications Periodic table and Classification of Elements



Academic Questions in Chemistry

Please check out our Test Your Knowledge page to see all Questions and Answers

The reaction involving an acid and a base is termed _____.

  • A. Hydrolysis
  • B. Neutralization
  • C. Combustion
  • D. Displacement
  • E. Decomposition
  • F. Sublimation

Which of the following is NOT a type of salt?

  • A. Acid salt
  • B. Basic salt
  • C. Double salt
  • D. Tripple salt
  • E. Complex salt
  • F. Normal Salt

The only metal that exist as liquid at room temperature is _____.

  1. Nickel
  2. Duralumin
  3. Mercury
  4. Lead
  5. Titanium
  6. Cesium

Separation of Mixtures:

Please read part 1 here

 

(5) Centrifugation

Centrifugation involves the use of a device called centrifuge to separate the lighter portions of a mixture from the denser portions through the spinning action of the centrifuge. Blood is a mixture and its components can be separated via centrifugation. 

Blood is considered a mixture because it is composed of liquid plasma and solid cells.

You may read on the red blood cells here

Image Credit: Microbiology Notes

Using blood as an instance, the test tubes containing the blood are inserted into the centrifuge. The centrifuge begins to spin/rotate when it's switched on; and this is allowed to continue for about 5 to 10 minutes. On bringing out the test tubes from the centrifuge, two different layers will be observed. These are:

  • The lower layer composed of solid cells that had sediment.
  • The upper layer containing the less dense plasma will be seen above it.

Next, the plasma can then be carefully decanted from the test tube. (Please see decantation above).

Below are some types of centrifugation
  • Differential Pelleting (differential centrifugation)
  • Isopynic Centrifugation
  • Density Gradient Centrifugation
  • Rate-Zonal Density-Gradient Centrifugation

 

(6) Sublimation

Matter exists in three states. These are:

  • Solid
  • Liquid
  • Gas

You may read on solid, liquid and gases here.

On heating a solid, it changes to liquid. If we continue heating, the liquid changes to gas. This is the usual sequence, however, in sublimation the heated solid does not pass through the liquid phase; instead, it changes to gas directly.

Sublimation is a process whereby a heated solid changes directly to gas without passing through the liquid phase

Such solids are said to sublime.

Examples of solids that sublime are ammonium chloride (NH4Cl), iodine crystals, sulphur, solid carbon(IV)oxide or dry ice, arsenic and naphthalene.

With regards to separation of mixtures, sublimation is used to separate two salts (or solids) in which one sublimes and the other does not. An example is a mixture of common salt and iodine crystals.

 

(7) Distillation

Distillation is a technique used to separate two or more miscible liquid that have different boiling points. (The boiling points of the different liquids may not be at a close range). The mixture of water and ethanol is a typical example since they are both miscible and have different boiling points. The mixture of water and acetone can also be separated via distillation.

Water boils at 100oC

Ethanol boils at 780C

Image Credit: Science Struck

To carry out distillation, the mixtures of both liquids are heated until the one with a lesser boiling point (ethanol in our instance) vapourizes or changes to vapour. The vapour is collected and cooled by passing it through a condenser. The condenser compresses this vapour into liquid as our ethanol is now collected as a distillate.

Think of a distillate as a liquid collected from the process of distillation after it has been passed through a condenser.

When we have two liquids of different boiling points, the liquid with a lesser boiling point is said to be more volatile while that with a higher boiling point is said to be less volatile

Distillation can also be used to:

  1. Separate a solid and a liquid: The liquid evaporates and is collected and condensed while the solid remains in the container.
  2. Purify liquid: This is true since only the pure liquid will vapourize leaving behind the solid impurities in the container.

Please read part 3 here


len

Alfred Ajibola is a Medical Biochemist, a passionate Academician with over 7 years of experience, a Versatile Writer, a Web Developer, a Cisco Certified Network Associate and a Cisco CyberOps Associate.


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Amazing facts in Chemistry

The only letters that failed to appear on the periodic table are letters:

J     &     Q

Gold and copper are the only two non-silvery colored metals. Please read some interesting facts about gold here


NOTABLE POINTS IN Chemistry

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