Can I get concentrations from this information?

Question

Fe^(3+) + SCN^(-) <---> [Fe(SCN)]^(2)

Tube 1 2 3 4 5 6 7 8 9
mL Fe(3+) [0.0] [1.0] [2.0] [2.5] [3.0] [3.5] [4.0] [5.0] [6.0]
mL SCN(-) [6.0] [5.0] [4.0] [3.5] [3.0] [2.5] [ 2.0] [1.0] [0.0]

can I find the concentrations?

Tube 1 2 3 4 5 6 7 8 9
absorbance 0 .420 .629 .658 .629 .509 .444 .260 0
[Fe(3+)] [ 0 ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ]
[SCN(-)] [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ 0 ]

How do I find it? I searched my notes and books and emailed prof... please help

Answer 1

Ah yes, the classic Iron Thiocyanate complexation lab.

To determine the concentrations for the first part, you need to know the concentrations of the stock solutions and the final volume of the solution you made. You can then use the formula:

C1*V1 = C2*V2

Where C is concentration and V is volume.

For the second part, I'm not really sure what you did in your lab. Usually you use the calibration curve you constructed from the first part to measure the concentrations in the second part. There is alot of ugly calculations to be done in there. Check your lab packet for more information.