Experiment 23 Advance Study Assignment: Determination of the Equilibrium Constant for a Chemical Reaction 1. A student mixes 5.00 mL of 2.00 x 10' M Fe(NO), with 3.00 mL of 2.00 x 10' M KSCN. She finds that in the equilibrium mixture the concentration of FeSCN2+ is 1.28 x 104 M. Find K, for the reaction: Fe (aq) + SCN- (aq) FeSCN2+ (aq). Step 1 Find the molarity of Fe3and SCN after the two solutions are mixed (no reaction has occurred) and the concentrations diluted. M Fert; MSCN- Step 2 What is the molarity of the FeSCN2+ at equilibrium? M FeSCN2+ Based on the stoichiometry of the reaction, what is the change in concentration for each of the two reactants? A[Fe] = ; A[SCN"]= Step 3 Adding the change in concentration to the original molarities, calculate the equilibrium concentrations of Fe- and SCN-. M Fest; MSCN- Step 4 Using the equilibrium concentrations and the expression for K, found in equation (1), calculate the value of the equilibrium constant K K