The report presents determination of equilibrium constant for the formation of a complex ion FeSCN2+. This was accomplished using a colorimeter to measure absorbance of some known concentration solutions in order to generate the calibration curve. The equation of the graph was used to compute the equilibrium concentrations of the reactants and products, needed to calculate the equilibrium constant for the reaction. I. Introduction:
The purpose of the experiment is to determine the equilibrium constant for the formation of a complex ion iron (III) thiocyanate (FeSCN2+). This ion is formed in the reaction of iron (III) ion with …show more content…
The average equilibrium constant for each of the four trials was calculated as well as the standard deviation. III. Data Tables and Observations:
Table 3: The calculated concentration of the solutions prepared from reactants in Table 1 and the measured values of their absorbance.
| |Molarity of FeSCN2+ (M) |Absorbance of FeSCN2+ |
|Experiment 1 |0.0002M |0.561 |
|Experiment 2 |0.0004M |1.043 |
|Experiment 3 |0.0006M |1.494 |
|Experiment 4 |0.0008M |1.804 |
|Experiment 5 |0.001M |1.987 |
Graph 1: Calibration curve with data from Table 3.
Table 4: Measured absorbance of equilibrium solutions prepared from Table 2 and their concentrations.
| |Absorbance |[FeSCN2+] (M) |