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Separating Mixtures (Charlotte) - Coggle Diagram
Separating Mixtures (Charlotte)
reasons why the purity of substances are important
to obtain useful substances
to study the properties
to avoid unwanted consequences
solid-solid
sublimation
used when one of the solid substances can sublime when heating
examples are: dry ice, iodine crystals, naphthalene or mothballs
application in daily lives
it is used in printing processes that uses heat to transfer dye onto paper or fabric to produce photographic prints
magnetic attraction
used to separated magnetic materials from non-magnetic materials in a mixture
examples are iron, steel, nickel and cobalt
example is iron fillings can be separated from sulfur powder in a mixture
application in daily lives
at scrap yards a strong electromagnet is used to salvage scrap iron and steel from other junk materials
In mining, it is used to separate magnetic ores from non-magnetic ores
It is used in hospitals to remove iron splinters from patient's eyes.
solid-liquid
filtration
used to separate an insoluble solid from a liquid
example is separating chalk powder from water
application in daily lives
tea bags prevent tea grains from spreading in water
sieve filters separates brewed coffee from ground coffee
air conditioner filter removes dust particles from incoming air
evaporation
method to separate a dissolved solid from a solution by heating it to dryness.
used if the dissolved solid is a heat stable substance (will not decompose upon strong heating)
The soluble solid that is not heat stable decomposes on strong heating
When is it used?
It is used if dissolved solid is a heat stable substance ( will not decompose upon strong heating)
process
the solution in the evaporating dish is heated until the solvent has dried up completely
dried salt crystals are obtained in the evaporating dish
application
common salt is obtained through evaporation of water
evaporation of sweat cools our body down and thus helps our body to maintain a constant body temperature during hot days
crystallisation
method to separate a soluble solid from its solution which is not heat stable
salt solution is filtered to remove any solid impurities
the filtrate is heated to remove most of the solvent until the solution becomes saturated. A saturated solution enables the crystals to form easily
The saturated solution is left to cool gradually to allow the formation of large-size crystals
the crystals are filtered and washed with little cold distilled water to remove impurities. They are then dried between filter paper
application in daily lives
table sugar is obtained from sugar beets or sugar canes by using crystallisation
used in the production of silicon which is the main component of most semiconductor devices including radios, computers, telephones and many other devices
chromatography
useful to separate and identify small amounts of substances that are dissolved in a solvent
eg. dyes in coloured ink
the different solvents move at different speeds on the chromatography paper
precautions
draw the starting line with a pencil and not a pen
a pencil is an element, so it is not made of dyes and will not be separated by the solvent to interfere the results
if you draw it with a pen, ink is made up of dyes which can dissolve in the solvent and interfere the results
The solvent front should be as high as possible
This ensures that the components in a sample are fully separated
use fine capillary tubes to place a small and concerntrated sample on the paper
this prevents the overlapping of components so that a clear and distinct lines or spots can be obtained
the solvent should be below the starting line
this prevents the sample from dissolving into the solvent so that it can travel up the paper
the jar should be covered with a lid when a volatile solvent such as alcohol is used
prevents the solvent from evaporating too fast
ensures that the jar is saturated with the solvent paper. This facilitates the movement of the solvent as it will not evaporate from the paper too quickly
process
a small amount of concerntrated sample is placed on the starting line of a chromatographic paper
the chromatographic paper is placed inside a beaker containing a solvent which is below the starting line
as the solvent moves up the paper, it separates the sample into its respective components
the chromatographic paper is removed before the solvent reaches the end of the paper
used to test the purity of a substance
used to identify the contents of a mixture
advantages
only a small amount of sample is required
it gives a fast and an accurate annaylsis of a sample
able to separate complex mixtures such as food dyes
result of the separated components on the chromatography paper is called chromatogram
how to annalyse?
when it has a single spot
it is pure and it is made up of one component
when it has two or more spots
it is a mixture
when it is smudged
too much of a sample is placed on the starting line
a small and concentrated sample should be placed using fine capillary tubes
ensures that the dyes are clearly separated in the distinct lines or spots
when the sample remains on the starting line
the sample does not dissolve in the solvent
we should change the solvent
when the solvents travel different distances
applications
in food industries, it is used to annalyse the safety levels of food sample
used to identify pollutants present in water
simple distillation
used to separate a liquid from a solid-liquid mixture
eg. pure water and sea water
features
thermometer
why is it placed near the opening of the condenser?
to measure the temperature of the vapour accurately
distillation flask
boiling chips
smoothen boiling by reducing bumping of liquid during boiling
prevent overheating of the liquid being distilled
condenser
receiving flask
narrow neck of the flask can reduce the loss of the distillate through splashing
application is daily lives
the technology of simple distillation improves the quality of drinking water in undeveloped countries by removing impurities and reducing waterborne illnesses
used to abstract the natural oils from flowers and herbs for making perfumes
liquid-liquid
fractional distillation
used to separate two or more miscible liquids in a mixture
eg. chalk powder from water
features
same like simple distillation but has a fractionating column and has a liquid-liquid mixture
fractionating column
allows a liquid with a higher boiling point to condense and fall back
applications in daily lives
separate petroleum
separate ethanol
separate gases
Four National Taps
WHY?
Water is a limited natural resource and to protect our country's sovereignty, we need to have more reliable water sources
What are they
Desalinated water
Water catchment areas
Imported water from other countries
NEWater