U4-3 - Extraction and Purification

Question 1

Name this piece of equipment

Answer 1

Separating funnel

Question 2

What is a separating funnel used for?

Answer 2

To separate immiscible liquids (the denser one is run out of the tap at the bottom).

Question 3

What should be added to a round-bottom flask before heating it?

(Reflux/distillation)

Answer 3

Anti bumping granules

Question 4

What is the purpose of anti bumping granules?

Answer 4

Allows liquids to boil smoothly and calmly.

Question 5

How does heating under reflux prevent loss of volatile substances during heating?

Answer 5

As substances vapourise and enter the condenser, they are cooled, condense into liquid and drip back into the reaction vessel.

Question 6

Complete the labels on this reflux setup

Answer 6

Question 7

Why does the water go in at the bottom of the condenser?

Answer 7

This allows the condenser to fill up fully and remain cold even if the water stops flowing (otherwise it would flow out).

Question 8

Name this piece of equipment

Answer 8

Condenser

Question 9

What is the purpose of recrystallisation?

Answer 9

To purify a crystalline product.

Question 10

Steps to recrystallise a solid:

1. Dissolve the crystals in __________.
2. Filter the hot solution to remove insoluble impurites.
3. Allow the filtrate to cool slowly.

Answer 10

Steps to recrystallise a solid:

1. Dissolve the crystals in a minimum volume of hot solvent.
2. Filter the hot solution to remove insoluble impurites.
3. Allow the filtrate to cool slowly.

Question 11

Steps to recrystallise a solid:

1. Dissolve the crystals in a minimum volume of hot solvent.
2. Filter the hot solution to __________.
3. Allow the filtrate to cool slowly.

Answer 11

Steps to recrystallise a solid:

1. Dissolve the crystals in a minimum volume of hot solvent.
2. Filter the hot solution to remove insoluble impurites.
3. Allow the filtrate to cool slowly.

Question 12

Steps to recrystallise a solid:

1. Dissolve the crystals in a minimum volume of hot solvent.
2. Filter the hot solution to remove insoluble impurites.
3. Allow the filtrate to __________.

Answer 12

Steps to recrystallise a solid:

1. Dissolve the crystals in a minimum volume of hot solvent.
2. Filter the hot solution to remove insoluble impurites.
3. Allow the filtrate to cool slowly.