16.1 Practical Techniques In Organic Chemistry Flashcards
(11 cards)
When would you heat something under reflux?
When you want to prepare an organic liquid without boiling off solvents, reactants or products
Why are anti-bumping granules used in reflux reactions?
To make sure the liquid boils smoothly, preventing the glassware from jumping/vibrating
Why mustn’t you put a stop in the top of a condenser during reflux?
Because pressure will build up, and the apparatus could explode
How should you make the water flow when using a condenser?
Water should enter at the bottom and leave at the top
What is the benefit of heating under reflux? (In terms of chemicals escaping)
Allows a liquid to be continually boiled, preventing volatile compounds from escaping the flask
What is the equipment that should be used in a reflux experiment?
- Pear-shaped flask
- Condenser
- Rubber tubing
- Stand and clamp
- Heat source (i.e bunsen burner)
What is the purpose of distillation?
Separates a pure liquid from its impurities
How do you purify an organic product? (Step-by-step process)
- Close lid of separating funnel
- Pour micture into separating funnel, place stopper on top of funnel, and mix the contents
- Allow the layers to settle
- Add some water to see which layer increases in volume (this is the aqueous layer)
- Place a conical flask below the separating funnel, remove the stopper, open the tap and remove the lower layer from the funnel
- Use another conical flask to collect the layer above.
What should you add into your separating funnel if you have used an acid catalyst?
Aqueous sodium hydroxide, to neutralise the solution
How should you neutralise your mixture of organic layers and aqueous layers?
- By adding aqueous sodium hydroxide
1. Add aqueous sodium hydroxide to the separating funnel
2. Shake the mixture, and open the lid to remove any carbon dioxide gas formed during neutralisation
What should you use to remove water from your organic product?
Magnesium sulfate (an anhydrous salt)
