RP5- Distillation Flashcards
Describe a method to carry pout distillation
Pour the mixture you want to separate into a round flask, with a still head that contains a thermometer
Attach to a condenser, with an ice cool collecting vessel
Add anti-bumping granules ad heat the flask gently using a Bunsen burner or a water bath
Heat to the boiling point of the desired product, and collect the condensed product in the ice cooled collecting vessel
In distillation, why is an ice cooled collecting vessel used?
To prevent/ minimise evaporation of the desired product
In a condenser, where does water go in and out and why?
Water in at the bottom of the condenser and out at the top
Water goes against gravity so the back flow of water is prevented and cooling is more efficient
Describe a method to produce an aldehyde by the oxidation and distillation of an alcohol
Uses intermediate distillation
Make acidified potassium dichromate (VI) by dissolving potassium dichromate (VI) in dilute sulfuric acid
Use a measuring cylinder to transfer 12cm3 of acidified potassium dichromate(VI) into a boiling tube. Cool the mixture in an ice cold bath
Use a pipette and pipette filler to add 2cm3 of alcohol to the boiling tube
Add antibumping granules to the boiling tube, attach it to a bung with a fitted right angle delivery tube that leads to a test tube in iced cold water
Heat the boiling tube to distill off the aldehyde, then test for it using tollens reagent
Describe how to carry out a tollens silver mirror test
Add 5 drops of sodium hydroxide solution to 2cm3 silver nitrate. A brown ppt will form
Add drops of ammonia until the brown ppt dissolves completely
Gently warm the tollens reagent in a water bath
Add ten drops of the aldehyde, and a silver mirror should form
What safety precautions can you take with tollens reagent?
Dispose of it thoroughly by rinsing it away with plenty of water
