Required Practicals

Question 1

Explain steps involved in measuring the EMF of an electrochemical cell (Cu/Zn)

Answer 1

Place copper strip into beaker with 50cm3 of 1 mol dm-3 CuSO4 solution
Place zinc strip into 50cm3 of 1mol dm-3 solution of ZnSO4

Use strip of filter paper soaked in saturated potassium nitrate solution for the salt bridge

Connect the half cells by connecting the metals using crocododile clips, a lead and a voltmeter

Question 2

Describe the steps involved in recrystallisation of an organic solid

Answer 2

1. Dissolve in minimum volume of hot solvent
2. Filter through filter paper
3. Cool filtered solution in ice beaker
4. Filter under reduced pressure with Büchner funnel
5. Wash crystals with distilled water
6. Dry crystals with absorbent paper

Question 3

Describe the steps involved in melting point testing

Answer 3

Thermometer with capillary tube containing samples strapped to it
Places in mineral oil
Heated
Temperature at which substance collapses

Melting point apparatus may also be used