Question

"The Determination of an Equilibrium Constant Prelab Assignment This experiment is separated into 2 parts. - In Part I the concentration of Fe3+ is 100x the concentration of SCN-. The purpose of Part I is to determine the value of Kc for the following reaction: Fe3+ + SCN- → FeSCN2+ In Part II the concentration of FeSCN2+ is 100x the concentration of SCN-. The purpose of Part II is to determine the value of Kc for the following reaction: FeSCN2+ + SCN- → Fe(SCN)32-"

Answer 1

You are determining equilibrium constants (Kc) for two reactions: Part I - Fe3+ + SCN- → FeSCN2+ with Fe3+ at 100x concentration of SCN-, and Part II - FeSCN2+ + SCN- → Fe(SCN)32- with FeSCN2+ at 100x concentration of SCN-. Kc is a ratio of concentrations of products to reactants.

Step-by-step explanation:

The experiment you are conducting involves chemical equilibrium reactions. In Part I, the equilibrium constant Kc is determined for the reaction Fe3+ + SCN- → FeSCN2+. This is done by varying concentration of Fe3+ and SCN-. Since the concentration of Fe3+ is 100x the concentration of SCN-, the ratio of concentrations will be used to calculate Kc.

In Part II, you are again determining an equilibrium constant Kc, for the reaction FeSCN2+ + SCN- → Fe(SCN)32-. But in this case, the concentration of FeSCN2+ is 100x the concentration of SCN-. This shift in concentration affects the equilibrium and therefore will result in a different value of Kc.

Remember, Kc refers to the ratio of the concentrations of the products to reactants, each raised to the power of its stoichiometric coefficient.

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