Intro to separation of mixtures

Separation of Mixtures-
Depending on the physical

properties of the parts within a

mixture different methods are used

For example jelly beans could be sorted mechanically with our hands by color :

Separation of Solids

Mechanical Sort by Hand (Hand Sort) -parts
of mix removed based on size, color or other
noticeable difference using hands or forceps.

Sieving
to separate solids of
differing sizes

a porous material like a screen is used to separate particles of
different sizes.

method is most commonly used to separate
different sizes of solids.

a series of sieves is stacked, with the screen of largest hole
size at the top

A magnet

Can be used to separate a magnetic substance from a non-magnetic substance

Magnetic metals include
● Iron
● Nickel
● Cobalt
● Gadolinium
● Dyprosium
● Neodymiun
Other metals like gold copper
silver and lead are not magnetic
but are weakly repelled by
magnets

Mechanical Sort by Floatation

(Buoyancy)

.

Floatation- mixture added to water and the low density
insoluble parts removed off top of water using hands,
forceps, or netting.
Water has a density of 1.00 g/ml. Materials that have a density less than 1 will float, Over 1 will sink

Sublimation is often
used as a purification
method for chemicals
that sublime such as:
Iodine
Ammonium Chloride
Sulfur
Naphthalene
Benzoic acid
Salicylic acid

Categorize

Options (5)

M&M's

Iron powder and Sand

Sand and rocks

Styrofoam and glass beads

Dirt and copper beads

What it is the easiest way to separate the following mixture

Hand sort

Magnet

Sieve

Buoyancy

Separation of solids from Liquids

Decanting

Liquids are crudely
poured off the top
of solids

Best for very dense
materials

Crude but fast method

Filtering

Mixture of
solid and
liquid

Stirring
rod

Filtrate (liquid
component
of the mixture)

Filter paper
traps solid

Funnel

Larger particles are trapped
in the paper filter and
soluble or smaller particles
flow through to collection
device
Insoluble solids are things
like
Dirt, Sand, Glass, Plastic,
Transition Metals and most
Solid Elements

Centrifugation

Spins sample very rapidly:
denser materials go to
bottom (outside)

0 Precipitates from reactions

Separate blood into serum and plasma
◦Serum (clear)
◦Plasma (contains red blood cells
‘RBCs’)

Blood

RBC

Serum

A B C

AFTER

Before

Parts of a Solution (Homogeneous Mix)

• Solvent- part that does the dissolving-

water is our universal solvent

• Solute- part that was dissolved

(salt)

Evaporating

Evaporation can be
used to separate a
solute from the
solvent in a solution

Works best when
the materials have
large differences in
boiling point

Remember water
boils at 100oc most
soluble solids
require at least
300oc

Crystallization- similar to evaporation used
when chemical may decompose or to purify
a chemical

Separation of Liquids

Adding Liquids Together

• Immiscible/Insoluble-

won’t dissolve

water and oil
layers appear

So heterogeneous mix

Can use a
separation funnel

Separation Funnel

Separates mixtures made of
immiscible/insoluble liquids with
different densities.

Glassware allows you to remove
different layers of your liquid
mixture through opening on the
bottom.

Miscible Liquids

• also called Soluble
will mix completely dissolve

• water and alcohol

can use distillation

Distillation

Used to separate
homogeneous mixtures of
soluble liquids based on
differences in boiling points
of substances involved

Mixture heated till only one part
boils and then condensed and
collected

Distillation
column

Activated Charcoal:
Removes color and odor through adsorption.
Used in water purification must be filtered
out

Activated charcoal use

1) Add activated charcoal
powder to the sample

2) Mix together completely and
let sit for a few minutes

3) Use Filter to remove
charcoal and trapped
impurities

Chromatography

Separates mixture based on AFFINITY
(attraction) of each component to the
surface of another material
All chemicals have different affinities to
something just can be complex
Separation occurs because higher Affinity
components travel at different slower
rates
Components must be soluble in the
mobile phase.

Mixture is usually liquid and is usually

drawn across chromatography paper

Thin-Layer Chromatography

Uses paper, thin plastic or glass trays to
identify the composition of pigments,
chemicals, and other unknown
substances.

It is very important not to disturb the chamber during the developing
process and slosh the solvent, the spots should be the same size,
the TLC plate should remain flat and not fold over or curve and the
solvent mark should be indicated upon removal from the chamber

Rf =

Distance Sample Travels
Distance

Solvent

front

Travels

Chromatography

Components

Affinity to Stationary Phase

Affinity to Mobile Phase

Blue

----------------

Insoluble in Mobile Phase

Black

✓✓✓✓✓✓

✓✓

Red

✓✓

✓✓✓✓✓

Yellow

✓

Mixture

Components

Separation

Stationary Phase

Mobile Phase

Illustration of Chromatography

✓✓✓✓✓✓

Match

Match the following with the most appropriate separation method

• salt water

• Sugar water

• Oil and Vinegar

• Food coloring in water

• Mixture of inks

Evaporation

Crystallization

Separation funnel

Activated charcoal

Chromatography

• Evaporation

• Crystallization

• Separation funnel

• Activated charcoal

• Chromatography

Match

Match the following with the most appropriate separation method

• sand and water

• sand and steel

• Alcohol and water

• Chlorine smell in water

• Sodium Chloride in water

Filter

Magnet

Distillation

Activated charcoal

Evaporation

• Filter

• Magnet

• Distillation

• Activated charcoal

• Evaporation

Calculations

Actual Amount
Percent Yield = ------------------- X 100%
Theoretical Amount

(actual - theoretical)
Percent Error = ------------------------------ X 100%
theoretical

Actual is value found in lab Theoretical is amount you should get

Multiple Choice

Calculate the percent error if the density of a metal is 2.67g/cm³ and your experimental value was determined to be 2.37g/cm³ .

• 11.236%

• 112.6%

• 30%

• 12.66%

Separation Review Questions

Multiple Choice

The beaker contains water and rubber pellets. Which method can be used to separate the mixture?

• magnetism

• filtration

• floatation

Multiple Choice

The beaker contains sugar and pebbles. Which method can be used to separate the mixture?

• magnetism

• filtration

• floatation

• sifting

Multiple Choice

The beaker contains water and salt Which method can be used to separate the mixture?

• evaporation

• filtration

• floatation

• sifting

Multiple Choice

Sugar and sand were added to water, then stirred. The mixture was then poured through the filter paper. Which statement correctly tells what happened?

• the sugar and the sand both stayed on the filter paper and the water went through the filter into the beaker

• the sand stayed on the filter paper and the sugar and water went through the filter into the beaker

• the water, sand, and sugar all went through the filter paper and into the beaker

• the water, sand, and sugar all stayed on the filter paper, and nothing went into the beaker

Multiple Choice

The separation technique that involves heating a solution until the liquid changes into a gas, leaving behind a solid is known as

• evaporation

• crystallization

• centrifuge

• chromatography

Multiple Choice

Dyes in water soluble markers may be separated by means of ____ due to their differences in affinities.

• Distillation

• Separation Funnel

• Chromatography

• Centrifuge

Multiple Choice

Oil and water are immiscible and may be separated by using

• leibig condenser
• separating funnel
• centrifuge
• distillation

Multiple Choice

Water and alcohol are easily separated by distillation because of their

• different densities
• different boiling points
• different colours
• different melting points

Multiple Choice

Which one of the following would you use to separate sand from iron filings?

• a bar magnet
•  filter paper
• distillation apparatus
• chromatography paper

Multiple Choice

Which one of the following is a disadvantage of evaporation?

• The solvent is not recovered

• It cannot be used for insoluble solids

• All of the solute is recovered

Multiple Choice

What is the best and easiest way to separate a mixture of different sized beads?

• Filter

• Distillation

• Chromatography

• Sieve

• Hand Sort

Multiple Choice

No matter what you do, sulfur will not dissolve in water, sulfur is _________ ?

• dissolved
• soluble
• insoluble
• aqueous

Multiple Choice

Filtration can separate a mixture because,,,

• the parts of the mixture have different density so they separate.
• some parts of the mixture are small enough to pass through the small holes in the filter paper and some don't.
• some of the particles in the mixture are attracted to the filter paper so it stays behind.
• some parts of the mixture boil faster than others so they evaporate first.

Multiple Choice

Activated Charcoal is used to

• Separate liquids

• Remove colors and odors from liquids

• Remove solids from liquids

• Remove gases from liquids

Multiple Choice

Which one of the following methods would be the easiest way to separate an insoluble solid and a liquid?

• evaporation

• filtering

• distillation

• chromatography

Multiple Choice

Used to separate a mixture of compounds using affinity to stationary and mobile phases

• Chromatography

• Filtration

• Decantation

• Centrifuge

Multiple Choice

This technique is based on the differences of the boiling point of the substance in the mixture.

• decantation

• distillation

• filtration

• chromatography