Potassium Chromate | 139.0925 | 1.27ppm | Total | ||||
Symbol | RMM | 1M | 1ppm | 0.1ppm | 0.01ppm | (g) | (g dm-3) |
K | 39.0983 | 39.0983 | 0.003248 | ||||
Cr | 51.996 | 51.996 | 0.002442 | ||||
O3 | 47.9982 | 47.9982 | 0.002650 | 0.008340 |
2.ii : Sulphuric acid, 0.18 and 3 mol dm-3
For both of these, the concentrated acid is used first. This must be handled with great care. All volumes of this must be pipetted out in perfectly dry pipettes.
0.18 mol dm-3 : Use 10cm3 acid, dilute to a final volume of 1dm3.
3.0 mol dm-3 : Use 42cm3 acid, dilute to a final volume of 250cm3.
2.iii : 1,5 Diphenyl carbazide (DiPC)
The method says to use 0.5g diluted to 200cm3 in propanone. By calculating how much DiPC is in each 50cm3, an easier value (for dilution) of 0.625g diluted to 250cm3 is obtained.
This solution must be made in a fume cupboard due to the solvent being propanone. It must also be stored away from light.