Module 4 - Organic Synthesis

Question 1

describe the method for separating an alkane from water

Answer 1

1- collect 10ml of the alkane and water mixture
2- pour the mixture into a separating funnel, ensuring the tap is closed, and stopper it
3- shake the funnel and leave it on clamp stand
4- once two layers have formed, remove the stopper
5- open the tap and drain the lower layer, then dispose of the water
6- add anhydrous calcium chloride (drying agent) in small amounts to the alkane while swirling until it stops clumping
7- after 20 mins filter the drying agent out of the alkane using a Buchner funnel

Question 2

describe the use of a Buchner funnel

Answer 2

-filters under a reduced pressure

Question 3

describe the method for recrystallising an organic solid from a solution

Answer 3

1- connect the Buchner funnel to the vacuum flask
2- connect the vacuum flask ti a tap and test it has suction
3- place filter paper into the Buchner funnel
4- collect 50cm3 of the hot benzoic acid solution in a beaker and place it into an ice bath for about 10 mins to allow it to recrystallise - add the minimum amount until saturated
5- pour the benzoic acid solution into the Buchner funnel
6- chill some distilled water and pour a very small amount over the crystals whilst in the funnel to rinse them
7- remove the filter paper from the funnel and leave it to dry