The well-known colorimetric determination of the equilibrium constant of the iron(III-thiocyanate complex is simplified by preparing solutions in a cuvette. For the calibration plot, 0.10 mL increments of 0.00100 M KSCN are added to 4.00 mL of 0.200 M Fe(NO[subscript 3])[subscript 3], and for the equilibrium solutions, 0.50 mL increments of 0.00200 M KSCN are added to 4.00 mL of 0.00200 M Fe(NO[subscript 3])[subscript 3. Students are able to complete data collection in about 30 min compared to 1.5 h using the standard procedure. The equilibrium constant is 113 [plus or minus] 3 at [approximately]20 [degrees]C. (Contains 3 tables.)