of all ions at equilibrium: [FeSCN2+] eq, [SCN-] eq, and [Fe3+] eq. 2. The reaction is represented by the following equation: Fe 3+ + SCN – <—-> FeSCN 2+. Thanks. Frank and Oswalt report a molar absorptivity (ε) for FeSCN2+ of 4700L/(mol*cm). When Fe 3+ and SCN-are combined, equilibrium is established between these two ions and the FeSCN 2+ ion. To determine the value of K eq, you must prepare a series of solutions, each of which contains known initial concentrations of Fe3+ (aq) and SCN − (aq) ions. Determination of the Equilibrium Constant for FeSCN2+ 1. 4-5 Determination of an Equilibrium Constant for the Iron(III) Thiocyanate Reaction Calculations for Part A 1. If two or more reactions are added to give another, the equilibrium constant for the reaction is the product of the equilibrium constants of the equations added. Purpose. Top. This question hasn't been answered yet Ask an expert. These values are used to determine the equilibrium concentrations and equi- librium constant for the reaction. In Part A of this experiment, you will prepare FeSCN 2+ solutions of known concentrations, measure their absorbances at 470 nm, and produce a calibration curve. Calculate and record in lab notebook the [FeSCN2+] in each solution and its absorbance. There are some circumstances in which, given some initial amounts and the K eq, you will have to determine the concentrations of all species when equilibrium is achieved. 2. . The purpose of this lab is to find the value of the equilibrium constant, K c. First, you will prepare a series of Fe+3(aq) + SCN-(aq) ⇌ FeSCN+2(aq) K c = [FeSCN+2] [Fe+3][SCN−1] Page I-2-2 / Determination of an Equilibrium Constant Lab. Determine the value of the equilibrium constant, K eq, for the reaction. 2+Frank and Oswalt report a molar absorptivity (ε) for FeSCN of 4700L/(mol*cm). Using this value, I used the equation for the K constant of an equilibrium: $$\mathrm{K} = \frac{[\ce{FeSCN^2+}]}{[\ce{Fe^3+}][\ce{SCN^-}]}$$ $$\mathrm{K} = \frac{\pu{6.39e-5}}{0.002^2}$$ $$\mathrm{K} = 15.975$$ This did not turn out to be the correct answer, but I'm not sure why. Write the equlibrium expression for the reaction system. K eq. Chemical Equilibrium: Finding a Constant, K c. The purpose of this lab is to experimentally determine the equilibrium constant, K c, for the following chemical reaction:. K 1, K 2, etc. In each beaker, there is an extreme excess of Fe3+ which forces the equilibrium far enough to the right that the [SCN–] can be assumed to be near zero and the [Fe3+] as remained essentially unchanged. What is the accepted value of the equilibrium constant of Fe(SCN)2+ (ten bucks says you won't find it)? Find The Equilibrium Constant For This Reaction If 298 = 0.14 V And 1 Electron Involved . Calculating Equilibrium Constant Values Learning Objectives. Because a large excess of Fe+3 is used, it is reasonable to assume that all of the SCN- is converted to FeSCN2+. The absorbance in then put into Beer-Lambert’s law, A = εbc, to find concentration and ultimately the equilibrium constant. The equilibrium concentrations of the three ions will then be experimentally determined. NAME_____ Post Lab Assignment 1. The purpose of this experiment was to verify the formula of FeSCN^2+ and to determine its formation constant by using a spectrometer. Prepare and test standard solutions of FeSCN 2+ in equilibrium. Any help would be appreciated. Adding Two or More Equations. 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