PhET: Solution Concentrations and Beer’s Law in UV-VIS Spectrochemical Analysis Dr. Jursich UIC, Dept. of Chemistry Learning Objectives: Understand effects of dilution, draining, and solvent evaporation on solute moles and molarity concentration of solutions. Demonstrate principles of Beer’s Law and apply it to the analysis of different solutes in aqueous solutions. Experimental Objectives: Quantitatively measure mass of known volumes of two unknown liquids in order to distinguish between the two liquids. For a tutorial on introduction on Beer’s Law see: Labflow video on Beer’s Law and Standard Curve Analysis, Chem Libre textbook at mental_Modules_(Physical_and_Theoretical_Chemistry)/Spectroscopy/Electronic_Spectroscopy/Electronic_Spectroscopy_Basics/The_Beer-Lambert_Law Procedure: Go to . There you will find the cover page as shown below. This will be a three part experiment. Part 1: Examine influence of dilution, evaporation, and draining on the concentration of solution Part 2: Demonstrating linearity of Beer’s Law Part 3: Determine concentration with Beer’s Law Click on “Concentration to start Part 1 and it brings you to set-up on right side. Here, several control features are highlighted in red and described below. “Faucet handle” allows addition of solvent “Drink mix” identifies solute to be added to solution. Shaking it adds solute to solution. “Solute Selector” (upper right). Allows one to select solute. Currently on “Drink mix” but can be change to numerous more interesting compounds by clicking on the downward triangle at right.
“Concentration Sensor” Click and dragging this sensor into the solution will allow concentration to be read on meter. “Drain valve” allows one to drain out solution. “Evaporation” allows one to remove solvent from solution. And since all solutes are nonvolatile solids, all solute stays in the container during evaporation.