CHEM 404 Lecture Notes - Lecture 5: Potassium Thiocyanate, Equilibrium Constant

• School: UNH
• Department: Chemistry
• Course: CHEM 404
• Professor: John Tsalavas

Document Summary

Discuss the creation of your calibration curve (absorbance versus concentration of [fe(scn)]2+) by using the initial [fe3+] of solutions 1-5. Fe3+ + scn- [fe(scn)]2+ (pale yellow) (colorless) (blood red) The substance i analyzed spectrophotometrically was the concentration of [fe(scn)]2+. The calibration curve plotted absorbance versus concentration of [fe(scn)]2+ in substances 1-5 to determine a linear regression known as beer-lamberts law. Le ch telier"s principle is a concept that when a system at equilibrium is disturbed, the position will shift in a way that will counteract the effect of the disturbance. This is related to the changes in concentrations when more of one substance is added the solution adapts to counteract the disturbance so it can return back to equilibrium. Equilibrium position moves to the right, using up some of the additional reactants and produces more fescn2+: when preparing equilibrium solutions 6-10, we did not dilute the fe(no3)3 as we did in substances 1-5.