Category : Natural Sciences

Quantum Chemical Models of Electronic Transitions of Conjugated Dyes

By: Brittany Schaum Abstract                   UV-Vis spectroscopy was used to determine the energy of transition, △E  , from the highest occupied molecular orbital (HOMO) to the lowest unoccupied molecular orbital (LUMO) of several cationic dyes. Each dye contains a conjugated, hydrocarbon π system with nitrogens at each end, which act as potential barriers for the π electrons in these systems. In this experiment, we have treated each dye as a one-dimensional “particle in a box” in order to simplify the […]

Synthesize Eutectics and Melting Point Comparison

Purpose of the Experiment The purpose of this experiment was to synthesize various eutectics and compare the melting points of the eutectics to their original components. In this experiment, we made four different eutectics. A mixture of choline chloride and urea was made, as well as a mixture of choline chloride and water. A mixture of choline iodide and urea was made, as well as a mixture of choline iodide and water. These eutectics were made because they were the […]

Solution Density and Partial Molar Volume as Functions of Concentration

Solution Density and Partial Molar Volume as Functions of Concentration By: Melissa Michaels Abstract A simple NaCl solution was used to model densities of solutions versus the molality of that solution.  This simple solution was then done with organic solutions including methanol, 1-propanol, and 2-propanol.  Using the derivative of the slope when plotting density versus molality we were able to show the partial molar volumes of the solutions.   1. Introduction The purpose of this experiment was to demonstrate the […]

BCA Protein Concentration Assay

Objective Utilizing Beer’s law, known concentrations of bovine serum albumin (BSA) are reacted with bicinchonic acid (BCA) to create a standard curve of absorbance vs. concentration of protein.  This curve is then utilized to determine the concentration of protein in an unknown solution. Introduction Beer’s law () tells us that the light absorbance (A) of a solution is proportional to the concentration of the protein (c) within the solution, the light path (b) and the extinction coefficient of the protein.  […]

Synthesis of Aspirin

Synthesis of Aspirin By: Jon Torre Purpose: To determine which of four catalysts yields the fastest reaction rate in the acetylation of salicylic acid (1) to form acetylsalicylic acid (2). Reactions: Procedure and Results: Aspirin Synthesis    Tap water was heated on a steam bath in a 250 mL beaker. The temperature of an alcohol thermometer was equilibrated in a beaker of room temperature tap water. Salicylic acid (1.00 g + 0.005 g) and acetic anhydride (2.0 mL + 0.05 mL) were […]

Investigating Polyphosphates with 31P NMR Spectroscopy

Abstract The experiment investigated the use of 31P NMR spectroscopy to determine the structure of polyphosphate anions. The structures of two cyclic (P4O124- and P3O93-) and two linear (P3O105- and P2O74-) were found. Introduction Phosphorus (V) has many polyphosphate oxo-anions which usually existing as either linear or cyclic phosphates. It is known that the linear phosphates are of the form [PnO3n+1](n+2)- and the cyclic phosphates in the form [PnO3n]n- (1). Two of these were synthesised: P3O105- and P4O124- using the […]