CH111 Lecture Notes - Lecture 5: Potassium Thiocyanate, Toxic Equivalency Factor, Equilibrium Constant
Document Summary
Experiment 5: determination of a reaction equilibrium constant using absorption. This is found through the creation of a. Bee(cid:396)"s la(cid:449) plot usi(cid:374)g a(cid:271)so(cid:396)ptio(cid:374) spe(cid:272)t(cid:396)os(cid:272)opy of the fo(cid:396)(cid:373)atio(cid:374) of pe(cid:374)taa(cid:395)uathio(cid:272)y(cid:374)a(cid:374)atoi(cid:396)o(cid:374) (iii) ion, fe3+. A colorimeter was set up to measure the absorbance for the mixture of each beaker. A chemical reaction can occur in two different processes, a forward direction where the reactants form products, or the reverse reaction where the products form reactants. Once equilibrium is reached, the rates of the forward and reverse reaction are the same. During equilibrium, reactants are still forming products and products are still forming reactants, but just at the same rate. the absorbance readings for sample #1-8 were 1. 249, 0. 901, 0. 686, 0. 446, The equilibrium constant was 351, and the percentage error of equilibrium constant was 154%. That meant a lower concentration of fe3+ ions resulted in a lower absorbance value. As the result, a higher percentage error meant the resulted absorbance readings were too high.
