Crystalisation

Question 1

4 steps of recrystallisation

Answer 1

1- sample dissolved in min vol of hot water
2- solution filtered hot
3-filtrate cooled in ice form crystals
4- crystals collected by filtration, washed with cold water and left to dry

Question 2

Step 1- why min vol and hot water?

Answer 2

Obtain satuarted solution
Increase yield/reduce amount left in sol
Enable crystallisation (on cooling)

Question 3

Step 2- why filtered hot?

Answer 3

Get rid of insoluble impurities

Question 4

Step 3- why cooled in ice?

Answer 4

Increase amount of crystals formed

Question 5

Step 4- why washed with cold water?

Answer 5

Remove soluble impurities