Heating under Reflux

Question	Answer
When is refluxed used?	To prepare an organic liquid without boiling off the solvent, reactants or products.
What temperature does refluxing boil solutions at?	A fixed temperature
Draw a diagram of the apparatus used	stand and clamp pear-shaped flask condensor rubber tubing heat source
Step 1.	Assemble apparatus
Step 2	Add anti-bumping granules to liquid ensure smooth boiling
When are anti-bumping granules added?	Before condensor is fitted and before liqiud is boiled
Why?	Enables a liquid to be continually boiled whilst a reaction is taking place Prevents glassware vibrating
Step 3.	Apply thin layer grease to ground-glass joint of condenser
Step 4.	Place condenser carefully into flask and gently rotate condenser back and forth to provide a good seal
Step 5.	Condenser is kept in upright position and clamped loosely as the glass outer jacket is fragile
Why should you never put a stopper in the condenser?	As you would have a closed system and pressure would build up inside as heated air is expanded.
Purpose of rubber tubing	Connect inlet of condensor to tap and outlet to sink.
Where does water always enter the condenser?	At the bottom and leaves at the top
What is the role of the condenser in the reflux reaction	Ensures any vapour produced from reaction condenses and drips back into the flask.
What heat source may be used if the reaction is carried out under 100'c?	Water bath.

Resource summary

	Created by josephw weetch over 6 years ago