organic synthesis

Question 1

all parts of dessssss apparatus

Answer 1

1. round bottom or pear shaped flask
2. receiver
3. screw tap adapter
4. condenser
   5 still head

Question 2

describe heating under reflux

Answer 2

water enters the condenser at the bottom and leaves at the top to ensure that the outer jacket of the condenser is completely filled with a constant supply of cold water
this promotes most efficient cooling of the vapor in the condenser

Question 3

describe heating by distillation

Answer 3

the liquids in the mixture have different boiling points
the liquid with the lowest boiling point (the most volatile) will boil first
the boiling point can be read off the thermometer
the vapour of the liquid with the lowest boiling point will condense back into a liquid in the condenser
the liquid with the lowest boiling point is separated first into a collecting flask

Question 4

define drying agent

Answer 4

anhydrous inorganic salt that readily takes up water to become hydrated

Question 5

examples of drying agents

Answer 5

magnesium sulfate - general drying
calcium sulfate - general drying
calcium chloride - drying hydrocarbons

Question 6

how to obtain a pure sample of the organic liquid from the reaction mixture

Answer 6

1. use a separating funnel to separate the organic layer from the aqueous layer
2. add an anhydrous salt to the organic liquid to act as a drying agent and remove any remaining water - add until the salt swirls freely and filter to remove solid salt
3. redistil the remaining liquid and (if the boiling point is know) collect the fraction at this temperature to obtain the pure dry liquid

Question 7

what does the density values tell us

Answer 7

more dense layer is usually the aqueous layer and is found at the bottom of the pear shaped flask
less dense layer is usually the organic layer and is found at the top of the pear shaped flask