chapter 16 - synthesis Flashcards
1
Q
why do we add anti-bumping granules
A
to avoid rattling the glassware upon boiling, stops big bubbles forming
2
Q
where does the water enter a liebig condenser
A
at the bottom so that the condenser is always filled
3
Q
what do we do to glass joints
A
grease them
4
Q
how to use a seperating funnel
A
- often water is obtained alongside an organic product
- they will have different densities so will form 2 different layers
- close tap on seperating funnel
- allow to settle, identify aqueous layer
- place over a conical flask remove the stopper and drain the lower level
- pour our the other layer
5
Q
how to remove acid impurities from a mixture
A
- add sodium carbonate
- place stopper and invert
- open tap on seperating funnel to remove gas then continue as normal
6
Q
how to dry an organic product and which to use
A
- anhydrous calcium chloride –> hydrocarbons
- anhydrous calcium sulfate –> general
- anhydrous MgSO4 –> general
7
Q
how much drying agent should you add
A
- keep adding the drying agent until it stops clumping
8
Q
what is the process for recrystallisation
A
- dissolve the crystals/solute in a MINIMUM amount of a HOT solvent
- heat gently until crystals just start to form
- cool AND filter AND leave to dry
9
Q
why do we use a minimum volume of hot solvent in recrystallisation
A
- we want to separate the pure crystals and any impurities
- so we need ONLY the crystals to be soluble in the solvent
- we use a minimum volume of solvent and heat it to ensure the crystals fully dissolve but nothing else does because the impurities will likely have a lower solubility than the crystals
10
Q
what is heating under reflux and what is its purpose
A
it involves strongly heating a substance with a vertical condenser setup to ensure reactants cannot escape
