Preparing 5 dilutions of 0.200M NiSO4?

Question

I’m supposed to be preparing five dilutions from 50.0 mL of 0.200M NiSO4 stock solution. Instructions say that I will need standard solutions with five different concentrations and all standards must have absorbances above 0.1 .

Maximum absorbance of 400 nm and molar absorption coefficient of 4.275 at 400 nm

Answer 1

You can make dilutions ranging from, say, the original stock of 0.2 M down to say, 0.02 M.  This covers a 10-fold range of concentrations, and for most colorometric studies, this will suffice.

mls 0.2 M stock   mls H2O   Final concentration

2 mls                  8 mls       0.02 M

4 mls                  6 mls       0.08 M

6 mls                  4 mls       0.12 M

8 mls                  2 mls       0.16 M

10 mls                0 mls       0.20 M