Chemical Equilibrium Lab Report

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Introduction

Equilibrium is the concept that in a chemical reaction where both the forward and reverse reactions occur, equilibrium is reached when both reactions are occurring at the same rate, thus once a reaction is at equilibria both the forward and reverse reactions are occurring at the same rate. For a given Chemical Equilibrium at a given temperature, keq can be calculated that will be constant no matter the initial values of the reactants and products. For a reaction: the equilibrium constant, . When a reaction has not yet equilibrium, or to test whether it has, an equilibrium quotient can be obtained using the same formula to obtain the reaction quotient, to determine whether a reaction will proceed or isf it is at equilibrium.
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Both of these compounds dissolve completely in water, and the iron bonds with six water molecules to form {Fe(H2O)}3+. When combined the iron and thiocyanate bond into thiocyanate, which is a red orange color, leaving nitrate and potassium as spectator ions. When the spectator ions and hydrates are ignored, the final BCE is:

In this experiment we should be able to find accurate values for the absorptivity constant of Fe(SCN)2+ at its max, as well as the keq of the equation we are studying. The reaction should have a K substantially greater than one, as Fe(SCN)2+ is not absorbent in water according to basic dissolution rules. This experiment is significant because if done correctly it could help to confirm the literature value of both the absorptivity constant and keq of this reaction. Furthermore, it provides a valuable case study in how to test and experiment with chemical equilibria.
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So the equation is where A is absorbance, is the absorbtivity constant, b is the path length of light, and c is the concentration of the solution. This part of the experiment used known concentrations of Fe(SCN)2+ in order to calculate the absorptivity constant. The concentration of Fe(SCN)2+ was obtained by reacting Fe3+ with huge excesses of SCN-, because since the value of SCN- is so large, we can assume that the reaction goes to completion in regards to Fe3+, and thus the initial concentration of Fe3+ is the same as the equilibrium concentration of Fe(SCN)2+. Using this knowledge, a spectrometer was used to calculate the absorbance of solutions of various concentrations of Fe(SCN)2+ at its max of 473.3 nm. The data points were then used to make a graph of Absorbance vs. concentration, with the slope of the linear regression of these points being equal to the absorptivity constant, since according to Beer’s law, and b in our case was

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