Experimental+procedure+for+determination+of+the+specific+surface+are+of+an+insoluble+substance

Back to Main
 * 1) Carefully weigh out 0.1 g of lead sulphate into each of 2 plastic scintillation vials
 * 2) Add 2 cm 3 of 35 S-labelled lead sulphate solution into each
 * 3) Place caps on vials and shake vigorously for 15 min
 * 4) Filter using a Buchner funnel and filter paper
 * 5) Pipette 0.5 cm 3 of each filtrate onto 2 aluminium planchettes
 * 6) Carefully transfer the planchettes using a tray lined with absorbent tissue to the wooden block beneath the infrared lamp in the fume hood
 * 7) Dry under the IR lamp taking care not to leave them too long in case of fire
 * 8) Transfer the dried planchettes to the Geiger counter on a tray
 * 9) Count both on shelf 2 of the Geiger counter – count for 1 min, repeat this 3 times and average the counts obtained
 * 10) Pipette 0.5 cm 3 of original 35 S-labelled lead sulphate solution (without the addition of lead sulphate powder) onto 3 rd planchette, dry and count as above
 * 11) Calculate the surface area, which should give a value of 10 4 – 10 5 cm 2 g -1