*Label five clean, dry test tubes with identification numbers 1 through 5 and prepare equilibrium systems according to the table below:

Tube #	1	2	3	4	5
mL dilute 0.00200M Fe(3+)	2.50	2.50	2.50	2.50	2.50
mL 0.00200M KSCN	0.50	1.00	1.50	2.00	2.50
mL 0.50 M HNO3	?	?	?	?	?
Total Volume	5.00	5.00	5.00	5.00	5.00

*Cover each tube with parafilm and mix the contents thoroughly.

*Measure the absorbance of each solution at 447 nm.

Determination of the Equilibrium Concentrations of All Species

*Find the equilibrium concentrations of the FeSCN(2+) complex from your calibration curve.

*Use the [FeSCN(2+)]equil determined with your calibration curve to calculate the equilibrium concentrations of SCN(1-) and Fe(3+).

Equilibrium Web Data Sheet

Introduction to Equilibrium

Calculations