Practical 20 Effect of surface area on rate gcse

GCSE PRACTICAL 20 PRACTICAL – Effect of surface area on rate :

HazCard : 81, 98A 

Each pupil/group needs: 

• 100 cm3 beaker

• 50 cm3 measuring cylinder

• stopwatch 

General apparatus: 

• tiles 

•  suitable knives for cutting rhubarb

•  rhubarb stalks (rich in Oxalic acid, could be swap with 0.1M oxalic acid (Tinned rhubarb work too) 

Chemicals :

•  acidified potassium manganate solution (about 100 cm3 per group) (Make 2L/ Class)

  • To make the potassium manganate(VII) solution: 

1.  put 4 or 5 crystals into a large jug with about 500 cm3 of 1.0 mol/dm3 sulfuric acid 

2. stir until the crystals dissolve and then 

3. add a further 500 cm3 of 1.0 mol/dm3 sulfuric acid and stir 

4. the solution should be pale purple