Organic techniques

Question 1

5 organic techniques

Answer 1

Reflux
Distillation
Separation
Removing traces of water
Measuring boiling point

Question 2

Why is reflux done?

Answer 2

Because substances are usually flammable and volatile so if heated normally in a reaction will evaporate or catch on fire before reaction is completed

Question 3

Reflux apparatus

Answer 3

A vertical Liebig condenser
Attached to a round bottom/ pear shaped flask with anti bumping granules being heated at the bottom

Question 4

Water in vs out in reflux?

Answer 4

Water in at bottom
Water out at top

Question 5

How does reflux work?

Answer 5

Due to heat, the mixture is continuously boiled, evaporated then condensed (due to cold water in condenser) and recycled back into flask = time to react

Question 6

Why use heating mantles in reflux?

Answer 6

Because to avoid naked flames which can ignite the flammable organic compounds

Question 7

Why is distillation done?

Answer 7

To separate substances which have different boiling points in a mixture (impurity’)
Or distill a product to separate it from the reaction mixture

Question 8

Distillation apparatus

Answer 8

Heating pear shaped/ round bottom flask with anti bumping granules
Thermometer
Slanted Liebig condenser
Delivery to a flask

Question 9

What does the thermometer do in distillation?

Answer 9

Shows the boiling point of what is evaporating at that time

Question 10

Boiling points when distilling a product from its reactant

Answer 10

If the boiling point is lower for products than reactants, as the product is formed it will be distilled off
Control heating idk anymore

Question 11

Boiling points when distilling an impure substance

Answer 11

When the thermometer changes, a different liquid is about to be collected as there is a change in bp

Question 12

How does distillation work?

Answer 12

Gently heats a mixture which evaporates substances out of flask in order of boiling point
Thermometer tells us the bp of what is being produced

Question 13

What is separation?

Answer 13

adding water to an insoluble product to dissolve water soluble salts (impurities) and leave non polar organic substance

Question 14

Steps of separation

Answer 14

Pour mixture into separating funnel
Add water
Shake funnel + allow to settle
Separates into 2 distinct layers: aqueous layer with impurities and organic layer
Run the tap to separate 2 distinct layers

Question 15

When do we remove traces of water with anhydrous salt

Answer 15

If using separation to remove impurities, the product may still contain trace amounts of water

Question 16

How to remove trace amounts of water with anhydrous salt?

Answer 16

Add an anhydrous salt which acts as a drying agent by binding to water and becoming hydrated
Add more until the salt is no longer lumpy
Filter to remove the newly hydrated salt

Question 17

Determining purity with boiling point

Answer 17

Use distillation apparatus to gently heat organic product
Read temp at which it is distilled (bp)
Look up bp in data booklets and compare this value: if the bp is higher it has impurities and boils at a range of temps