Mr. Heriberto MoranMED 1020012 May 2017Title: Chemical Equilibrium: Formation Constant of a Complex Ion SystemAim: The aim of this experiment was to determine the equilibrium constant, Kc, for the reaction between Fe3+and SCN-forming the soluble ion FeNCS2+by using a spectrophotometer.Theory and Relevant Equations: The equilibrium constant of a reaction shows the nature of thechemical system. Small Kcvalues (smaller than 1) show that the equilibrium favors the reactants.Large Kcvalues (larger than 1) show that the equilibrium favors the products. The Kcis affected by nothing except for temperature. Spectrophotometry is used for measuring the reflection or transmission properties of a material. Spectrophotometers are used to measure transmittance and absorbance or reflectance of solutions.Fe(H2O)63+ (aq) + SCN- (aq) ←→Fe(H2O)5NCS2+(aq) + H2O (l)Relevant Equation 1Kcis determined by reacting known amounts of Fe3+and SCN-to form an equilibrium where the blood red complex ion FeNCS2+ is formed.