[CincyER216]

Hey everyone. I haven't done chemistry in years and decided to re-take a chem lab course for fun. I have a determination of equilibrium constant lab to due. The initial data follows:

mixture           volume in mL, 2.00 x 10^-3        Volume in mL, 2.00 x 10^-3 M    volume of water)mL
                                Fe(NO3)3                                      KSCN       
1                                     5                                             1                                       4
2                                     5                                             2                                       3
3                                     5                                             3                                       2
4                                     5                                             4                                       1
5                                     5                                             5                                       0

Method I absorbance              [FeSCN] 2+

I am to find the initial number of moles of Fe3+ and SCN- in each mixture; the equilibrium number of moles for Fe 3+, SCN-, and FeSCN2+ in each mixture; and the equilibrium concentrations of Fe3+, SCN-, and FeSCN2+ for each mixture.

I understand that i need a spectrophometer cell, but if someone could walk me through the steps that would be great.
                                           

[Phlogiston]

The way we run this lab, you first construct a calibration curve relating the amount of absorption to a known conc. of iron thiocyanate.  Then, you can use that to determine the conc. of iron thiocyanate in the unknowns, which lets you figure out K.