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Seperating mixtures (Temperance) - Coggle Diagram
Seperating mixtures (Temperance)
Why?
To obtain useful substances
Eg: O2+N
To study properties
To avoid consequences
Purification techniques
Sublimation/magnetic attraction
Solid-Solid
Used for when solid substances
Eg of sublimed substances:
Dry ice
Iodine crystals
Napthelene
In printing process
Dye onto paper or fabric
Using heat transfer
can sublime when heating
Filtiration/Evaporation
Solid-liquid
Crystallisation/Chromatography
To separate soluble solid from
Steps to obtain soluble salt
1.Salt solution is filtered
2.Filtrate heated
(enables crystals to easily form)
3.Saturated solution is left to cool
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to remove most of solvent
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To remove impurities
Crystallistaion in daily life
Important in food tech
Used in production in silicon
main part of devices
its non-heat-stable solution
Chromatography
To separate dissolved small amount of substances
Different parts in mixture have
Process
1.Small amount of concentrated sample
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different solubility in solvent
Usefulness
Identify contents of mixture
Test purity of a substance
Advantages
Only small sample is needed
Fast and accurate analysis
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Food/dyes/poison
Simple distillation
Condenser
Ensures coldest part of condenser
Is present before vapour escapes
Boiling stones
Smoothen boiling by
Reducing bumping of liquid
Thermometer
Placed near opening of condenser
to measure vapour temperature
Conical flask
Used as receiving flask
Application
Obtaining desalinated water
Imporves quality of drinking water
Used to extract the natural oils
from flowers/herbs
When substance is distilled
Liquid collected is distillate
Gentle blue flame used for heating
If distillate is volatile
Fill conical flask with ice
The temperature of BP remains same
Evaporation used if
Process
1.The solution in the dish is heated
Dried salt crystals are
obtained in the dish
until solvent fully dried
Application in daily life
Evaporation of seawater gives us
Evaportaion of sweat to keep us cool
common salt
dissolved solid is heat-stable
Liquid-liquid
Fractional distillation
Liquid with lower boiling point
Fractioning column
Allows liquid of higher BP to condense first
Distilled first
Application
Used in oil refineries
to separate petroleum
Used to separate ethanol products
Separates liquified noble gases
Filtiration
Features:
Small liquid particles
Large solid particles
trapped on filter paper
passes through pores
Residue=
Liquid passing through pores=Filtrate
insoluble solid on filter paper
Residue
Filter funnel
Filter paper
Filtrate
Pores
Filter paper has tiny pores
insoluble solid larger than pore no pass through
Sand and water
Brewed coffee containing ground coffee
Insoluble silver chloride
Residsue=silver chloride
Filtrate=sodium nitrate solution
in sodium nitrate solution
Residue=ground coffee
Filtrate=brewed coffee
residue=sand
Filtrate=water
Application of filtration
Sink filter removes
large food particles
from entering drainage system
Tea bag prevents
tea grains from spreading in water
Sieve separates
brewed coffee from ground coffee
Filtration is used to remove
suspended soils from greases in used water
Filtration removes
unwanted impurities from rainwater
Filtration in human body
The kidneys of mammals clean the blood
To remove bad stuff
The nostril hair filters and removes
Dust and large suspended particles
From inhaled air
Singapore uses reverse osmosis
It is a filtration method
Removes
Eg:salts
large unwanted particles from seawater
Uses special type of membrane
to obtain desalinated water
Precautions for chromatography (must memorise)
Draw starting line with pencil
Pencil is an element
Will not be separated by solvent
Will not interfere with results
Use callipary tubes
Prevents overlapping of components
To place small amount of solvent
Solvent should be below starting line
Prevents sample from
dissolving into solvent
Solvent should be high as possiblre
Ensures components are fully separated
using volatile solvent is used
Prevents solvent from evaporating
Ensures jar is saturated with
solvent vapour
Cover jar with lid
How to analyse chromatogram
1 spot
Different distance travelled
M more soluble
Travels faster+further
X is a pure substance
1 component only
3 spots
Complete matching spots
X=Y
Sample X is in mixture
3 components
Smudge
Partial matching spots
X and Y have 2 matching parts
too much X on starting line
X still on starting line
Sample made up of other samples
2 components of Y and 1 Z
X no dissolve in solvent
Change solvent
