Mixtures, Solutions, Suspensions and Colloids

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MIXTURES, SOLUTIONS, SUSPENSIONS AND COLLOIDS

MIXTURES
A mixture is a combination made up of two or more different substances which are mixed but are not chemically bonded. There are also types of mixtures such as homogeneous mixtures and heterogeneous mixtures.

SOLUTIONS
A solution is defined as a homogeneous mixture composed of a solute; a substance dissolved into another substance known as a solvent. They can also be defined as groups of molecules that are mixed up completely in even distribution all around the mixture.

SUSPENSIONS
This is defined as a heterogeneous fluid whose particles are in larger quantity for the fluid it is supposed to be dissolved into. Unlike what is soon going to be defined, colloids, suspensions’ particles eventually settle over time if left undisturbed.

COLLOIDS
This is defined as a substance dispersed evenly throughout another substance. A colloid consists of two phases in its entire substantial form which are a dispersed phase of the solution and a continuous phase. A colloidal system may be solid, liquid or gaseous in form. Some colloids are translucent which causes particles to be scattered throughout the colloid, whilst other colloids may be opaque or have a slight color.

PROPERTIES (Particle Visibility, Particle Distribution, Filterability, Particle Size, Nature, Appearance)

SOLUTION
Not visible to the Naked Eye
Even throughout/Completely dissolved
Not be easily separated
Technically small
Homogeneous
Transparent

SUSPENSION
Easily seen with the Naked Eye
Equally dispersed/ Not dissolved at all
Easily separated
Large
Heterogeneous
Opaque

COLLOID
Hard spotting with The Naked Eye
Undissolved particles /Partially dissolved
Not easily separated
Intermediate
Heterogeneous
Translucent

TABLE SHOWING PROPERTIES OF DIFFERENT TYPES OF MIXTURES

METHODS OF SEPARATION

There are several methods of separation. These methods vary based on whether the components are solid, liquid or gas. The most common known methods are as follows: 1. Distillation
2. Separating funnel
3. Filtration
4. Solvent extraction
5. Paper chromatography
6. Recrystalization
7. Evaporation
8. Sublimation

DISTILLATION

This is defined as the process of boiling a liquid and condensing and collecting the vapor. The liquid is collected in a distillate. It is used to purify liquids and to separate liquid mixtures. There are two main forms of distillation which are simple distillation and fractional distillation.

SIMPLE DISTILLATION
This is used to obtain a pure solvent from a solution; for example, pure water from sea water. The impure liquid is heated until evaporation which will produce a pure vapor. This vapor is condensed by cooling and the pure liquid is obtained.

FRACTIONAL DISTILLATION
This is used with liquids of similar boiling points. Effective separation can be achieved by using a fractionating column attached to the distillation vessel and filled with glass beads. Vapor from the liquid rises up the column until it condenses and runs back into the vessel. The rising vapor in the column flows over the descending liquid. The vapor in the column has more volatile components towards the top and the less volatile components at the bottom. Various fractions of the mixture can be drawn of the mixture can be drawn off at points on the column.

SEPARATING FUNNEL

One can use a separating funnel to separate a pair of immiscible liquids. This is due to the distinct layers between the two liquids, in which the more dense liquid will be at the bottom, while the less dense liquid will be at the top.

FILTRATION

This is defined as a method of separating suspended solids from liquids, which in this case means both liquids and gases. The solid may be an impurity to be removed from a liquid product, or the desired product, so the liquid can be discarded. The separation of water from soil can be an example where this type of separation can be used....
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