Experiment #11 Chemical Equilibrium: Determination of an Equilibrium Constant

Introduction

Chemical equilibrium is a crucial concept in the field of chemistry, and the determination of equilibrium constants is essential for understanding and predicting chemical reactions. The objective of this experiment is to determine the equilibrium constant for the reaction between iron(III) ions and thiocyanate ions.

Theory

Chemical equilibrium is the state in a chemical reaction when the concentrations of the reactants and products remain constant over time. Le Chatelier’s principle states that when a system at equilibrium is subjected to a change, it will adjust to oppose the change and establish a new equilibrium. The equilibrium constant, K, is a measure of the extent of a chemical reaction at equilibrium and reflects the concentration of reactants and products. It is a crucial parameter in determining the direction and extent of a reaction.

Experimental Methods

The experiment was conducted using a spectrophotometer to measure the absorbance of the reaction mixture at different time intervals, from which the equilibrium constant was calculated using the Beer-Lambert law.

Results and Discussion

The data collected during the experiment showed a clear trend in absorbance over time, allowing for the calculation of the equilibrium constant. The experimental value obtained was compared to the theoretical value, and the results were analyzed to determine the accuracy and precision of the experiment.

Limitations and Sources of Error

Possible sources of error in the experiment include instrumental errors, variations in sample preparation, and human error in recording measurements. These factors may have affected the accuracy of the results obtained in the experiment.

Conclusion

The experiment provided valuable insights into the determination of equilibrium constants and the factors that influence them. The significance of equilibrium constants in predicting and manipulating chemical reactions was reaffirmed through the experiment.

Future Recommendations

To improve the experiment, it is recommended to conduct multiple trials, use higher precision instruments, and control for external factors that may affect the reaction. Further research areas related to chemical equilibrium include investigating the effect of temperature and pressure on equilibrium constants.

References

1. Atkins, P., & De Paula, J. (2011). Atkins' physical chemistry. Oxford: Oxford University Press.
2. Chang, R. (2010). Chemistry. New York, NY: McGraw-Hill.
3. Tro, N. (2017). Chemistry: A molecular approach. Boston, MA: Pearson Education.