Question

Beers law solve for E3 and E4 showing work

Part II. Equilibrium Constant Calculations

1. Calculate the initial moles of Fe3+ and SCN- for solutions E2 through E6 and record these values in the table on your Data Sheet. You obtain the moles of the reactants by multiplying their molarity by the volume (in L) of their solution used.

2. Determine the equilibrium concentration of FeSCN2+ for each of the solutions E2-E6 from your Beer’s Law plot. Using these equilibrium concentrations, the number of moles of SCN- can be calculated in each mixture. Record both the equilibrium concentrations and equilib- rium numbers of moles in the table on your Data Sheet.

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Determining the Equilibrium Constant for the Formation of the Iron Thiocyanate Ion Using Specrophotometry

3. Using the ICE table approach described in the Introduction, you can now calculate the equi- librium concentrations of the Fe3+ and SCN- ions using the equations below:

   moles of Fe3+(eq) = moles of Fe3+(initial) – moles of FeSCN2+(eq)

   - - 2+ moles of SCN (eq) = moles of SCN (initial) – moles of FeSCN (eq)

   (Don’t forget that you obtain moles of a solute by taking the molarity of its solution and multiply it with the volume in L!)

4. Calculate the equilibrium molarity of the SCN- and Fe3+ ions by dividing their number of moles at equilibrium by the total final volume (in L) of the equilibrium mixture.

5. Having all equilibrium concentrations of the components of the mixture, calculate the value of the equilibrium constant for each mixture.

Part II. Equilibrium Mixtures Stock solution concentration, [NaSCN] = 0.00200 Min 0.10 M HNO3) Stock solution concentration, [Fe(NO3)3] = 0.00200 M (in 0.10 M HNO3) E1 E2 E3 E4 E5 E6 Solutiom Temp (°C) 22.3 22.3 22.3 22.3 22.3 22.3 Vol. of 0.00200 M NaSCN used (L) 0 0.00100 0.00200 0.00300 0.00400 0.00500 Moles of SCN (initial) 0 0.000002 0.000004 0.000006 0.000008 0.00001 Vol. of 0.00200 M Fe(NO3)3 used (L) 0.00500 0.00500 0.00500 0.00500 0.00500 0.00500 Moles of Fe3+ (initial) N/A 0.00001 0.00001 0.00001 0.00001 0.00001 Vol. of 0.10 M HNO3 added (L) 0.00500 0.00400 0.00300 0.00200 0.00100 0 [FeSCN2+)eq (mol/ L) (from Beer's Law plot) 0 0.0000362399 0.0000822332 0.000120782 0.0001614177 0.000219739 Moles of FeSCN2 0 Moles of SCN 0 [SCNJeg (mol/L) 0 Moles of Fe3+ (e) N/A [Fe3+]eq (mol/L) N/A Absorbance (A) 0 0.085 0.161 0.226 0.326 0.364 Keq N/A (blank, no eqil.)