Different processes can be used to separate substances and mixtures. These include decantation to separate immiscible liquids by removing the upper layer, filtration to separate solids from liquids or gases using a filter medium, and centrifugation to separate mixtures by spinning. Other processes are crystallization to separate solids from solutions in crystalline form, distillation to separate pure liquid mixtures by vaporization and condensation, and evaporation to separate salt solutions by vaporizing the liquid. Chromatography also separates mixtures by passing them through a medium in which components move at different rates. Common substances that may be separated include water, salt, ammonia, methane, carbon dioxide, acids, sugars and vinegar.
Different Processes in Separating and Purifying Substances and Mixtures.docx
1. 1. Different Processes in Separating and Purifying Substances and Mixtures:
a. Decantation - the process of separation of liquid from solid and other
immiscible (non-mixing) liquids, by removing the liquid layer at the top from
the layer of solid or liquid below.
Examples:
separating of oil and water
separating dirt and water
separating kerosene and water
separating gasoline and water
separating milk and cream
separating blood and plasma
b. Filtration - is a process used to separate solids from liquids or gases using a
filter medium that allows the fluid to pass through but not the solid.
Examples:
Filtration of Tea or Coffee using a Seive.
Separation of chalk powder and water from their solution.
Vacuum cleaners
Filtration of sand particles from water or chalk powder.
Blood filtering in kidneys
c. Centrifugation -methods of separation where mixture is separated through
spinning.
Examples:
Removing fat from milk to produce skimmed milk.
Separating water from textiles.
Removing water from lettuce after washing it in a salad spinner.
Separating particles from an air-flow using cyclonic separation.
d. Crystallization - is a method of separating a solid from its liquid solution in the
form of pure crystals. It is a technique for purification of the substances. It
is a technique that separates a solid from its solution.
Examples:
Salt Harvesting
Crystallization of water to form ice cubes
Crystallization of honey placed in a jar
Formation of stalagmites and stalactites
2. e. Distillation - is an effective method to separate mixtures that are comprised of
two or more pure liquids. Distillation is a purification process where the
components of a liquid mixture are vaporized and then condensed and isolated.
Examples:
purification of alcohol,
desalination, crude oil refining
making liquefied gases
f. Evaporation - is a technique used to separate out homogeneous mixtures that
contain one or more dissolved salts.
Examples:
Puddles outside disappearing,
Clothes drying on a line,
The water level going down in a cup,
Steam from a hot shower or bath,
Using a hairdryer,
Ironing clothes by heating moisture,
Floors and cars drying after cleaning,
g. Chromatography - is the separation of a mixture by passing it in solution or
suspension, or as a vapor through a medium in which the components move at
different rates.
Examples:
Food coloring in food
Separating dyes
