SEPARATION OF SUBSTANCES Page 58* summary. HAND SEPERATION A mechanical mixture can be separated by hands, a magnet or a sieve.

SEPARATION OF SUBSTANCES

Page 58* summary

HAND SEPERATION

• A mechanical mixture can be separated by hands, a magnet or a sieve.

FILTRATIONDESIRED SOLID (RESIDUE) COLLECTS ON FILTER PAPERUNWANTED LIQUID (FILTRATE) IS DISCARDED.

FILTRATION

Evaporation

• Solution is put in an evaporation disk and heat is applied until all of the solvent has evaporated and only the solid remains.

DISTILLATION

Distillation

• We have two or more liquids.• We just want one liquid (distillate)• Each liquid has a different boiling

temperature. • The one with the lower boiling point will boil

first and it will be collected first.• It evaporates, condenses and gets collected.

Solvent Extraction

Extracting Solids from Solids: use of a solvent to dissolve the unwanted solids and just leave the desired solid.

Extracting Solids/Liquids from Liquids: we usually use a separatory funnel to do this.

Solvent Extraction

A Separatory funnel The original and added solvent are added and separate due to different densities. We use an added solvent that can dissolve what we want in it.Usually, the bottom layer is the added solvent that will collect the desired substance in it as it is soluble ( miscible) in it.After shaking, the added solvent and the substances that moved to it will be poured out and collected.

Separatory funnels

Separatory funnels

Recrystallization/fractional crystallization

• If the desired solid has some impurities, add just enough hot solvent to dissolve it. (maximum solid dissolved = satured solution)

• Allow solution to cool off, as the solvent evaporates off, crystals of pure solid will form.

• Hand separation or filtration is used after.

• http://www2.volstate.edu/chem/2010/labs/recrystallization.html

Last few notes…

There are 2 more methods…1. Gravity Separation2. Chromatography

They are found on page 56 and 57 and will be part of your following assignment.

Separation Method Assignment

For each of the required methods, you need to:1- write the title of the method2- give a brief explanation of how the method works ( in a way another Chem 11 student would understand)3- Give 1-2 examples of real mixtures that can be separated by the method.*4- For distillation and Solvent extraction (seperatory funnel), draw a simple diagram of the apparatus set up.

The Methods required of you

1- Filtration2- Distillation3- Solvent Extraction 4- Recrystallization 5- Gravity Separation6- Chromatography

• You have until Friday 28th to hand in your assignment.

• Use your textbook(53-58), my notes or any other resource you prefer to complete the assignment.