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EXPLORING DIVERISTY OF MATTER USING SEPARATION TECHNIQUES (SIMPLE…
EXPLORING DIVERISTY OF MATTER USING SEPARATION TECHNIQUES
why do we need pure substances?
production of medicine
avoid undesirable side effects due to impurities
production of food and beverages
have to ensure chemicals used are pure and safe for human consumption
EVAPORATION TILL DRYNESS
soluble solid from liquid
only for substances that do not decompose on heating
liquid from solution evaporates, leaving only the solid as residue behind
might not always be pure solid left behind - soluble impurities will be left behind with solid after process
application: produce evaporated milk
MAGNETIC ATTRACTION
magnetic solid from non-magnetic solid
application: separating scrap metal, removing iron splinters from the body etc
FILTRATION
insoluble solid from liquid
place filter paper in filter funnel, pour mixture onto filter paper - large solid particles will be left on the filter paper (residue), liquid will be filtered out (filtrate)
separation by size of particles - smaller particles (liquid) can pass through paper while larger particles (solid) cannot
application: human nose, kidneys
SIMPLE DISTILLATION
liquid from solution (can be solid-liquid or liquid-liquid)
https://drive.google.com/file/d/1d6cLT_-K2T5dUjvvTCycmjcqluEaza06/view?usp=sharing
different boiling points - liquid (with higher boiling point) boils and becomes steam, travels through the tube to cool down because of the water and become tiny droplets of liquid
application: producing distilled water, desalination (removing salt from seawater), producing alcoholic drinks, making perfumes
boiling chips --> smooth boiling
CRYSTALLISATION
soluble solid from liquid
solution heated to remove most liquid, heating stops when saturated solution forms, solution is left to cool, cooling leaves crystals (rapid cooling leaves small crystals, slow cooling leaves big crystals), crystals are washed and dried
application: production of silicon wafers, production of sucrose sugar from sugar beets & sugar cane
slow cooling --> bigger crystals, rapid cooling --> small crystals
easily purified --> solubility changes greatly with small change in temp --> large quantity of crystals can be obtained easily w/ small change in temp
FRACTIONAL DISTILLATION
two or more miscible liquids that have more than 25 degrees celsius difference in boiling points
https://drive.google.com/open?id=1eY3sPWqLJdFm7OybSNAL-PIps9azZWpr
https://drive.google.com/open?id=1bHLud8TbfHtYdVT1G6mQrrPUaYKVfv5D
fractional distillation has a fractionating column with glass beads to cool, condense and vaporise while simple distillation does not have a fractionating column --> more efficient than simple distillation because of fractionating column
simple distillation uses a distillation flask (has side arm) , fractional distillation uses a round bottomed flask (side arm absent)
fractional distillation has glass beads, simple distillation does not have glass beads
PAPER CHROMATOGRAPHY
solutes from solution
depends on relative solubility of solutes --> more solubility --> more dist travelled
when colourless chemicals are being separated, locating agents are used
drop of solution placed on pencil line near end of filter paper, filter paper dipped in solvent (solvent level below solution), solvent moves up paper, dyes move up acc to solubility
ratio of dist travelled by substance and dist travelled by solvent will be same (Rf value) - affected by temperature of solvent, type of solvent, type of paper and size of spot
application: identify colours in dyes, identify coloured products in food, detect pollutants in water
when chemicals are transparent --> use of locating agent --> react with colourless chemicals and make them visible
SUBLIMATION
solid that sublimes (changes to gas state) on heating from solid
heat the mixture with the mouth filter funnel facing downwards and a wet cloth to provide cool surface to cool the subliming solid such that the vapour solidifies (sublimes) in the filter funnel
USE OF SEPARATING FUNNEL
liquid from liquid (suspension)
SEPARATING SOLIDS USING A SUITABLE SOLVENT
solid from solid
use solvent that can dissolve one of the solids, conduct filtration so one of the solids is left behind as residue, evaporate filtrate till dryness to obtain the other solid, rinse solids to remove soluble impurities