logo

Category : General Chemistry Labs

Determining the pKa of Bromothymol Blue by spectrophotometry

James Robertson Chemistry 2220 Determining the pKa of Bromothymol Blue by spectrophotometry Abstract To determine the pKa of an acid-base indicator, specifically bromothymol blue, different amounts of both 0.1M NaOH and 0.1 M HCl were added to a solution of fixed concentration of bromothymol blue and the pH was monitored via pH meter. At different pH readings around the researched pKa of Bromothymol blue we measured absorbance of the buffer solution. By superimposing the absorbance graphs, two wavelengths of absorbance […]

Equilibrium

I. Purpose To study how stress affects a system’s equilibrium and to determine the concentration of the complex ion in solutions of unknown concentration as well as the equilibrium constant. Procedure LeChatelier’s Principle Part 1 Solid sodium chloride was poured into a test tube and the test tube was then filled ¾ full of distilled water.  The solution was then decanted into a second test tube and Cl– ions in the form of concentrated HCl were added. Part 2 A […]

Determining a Reaction Intermediate

By: Jaime Rodriguez Background: In this experiment, the concentrations of KMnO4 in each test tube were considered similar if their respective colors were similar. This step is what made it possible to calculate the amount of hydrogen peroxide in the original solution of melted ice. Unfortunately, the human eye is not keen to accurately detect the change in color intensity; therefore the colors in both test tubes may not have been very similar at all. Besides this method, there is […]

Diffraction Patterns from Polystyrene Beads and from Breath Figures

By: Ludmila Novikova Abstract: Before X-ray diffraction of crystals was applied to determine the arrangement of atoms in 1913, little was known about the geometric and stereochemical shape of molecules and about the science of crystallography in general. In fact, the atomic theory of matter was not completely accepted because there was no theory available to explain the existence of compounds of the same composition (Flack, 372). X-ray crystallography presented us with methods that would allow us to strike a […]

Analysis of Florida Well-Water

By: Timothy Pemberton Introduction: For this project, the purpose was to experimentally determine the qualities of a sample of well water including ‘hardness’, amount of minerals, and they types of minerals present. The results obtained will then be compared to other lab groups who also conducted the same experiments on the same sample of water to reveal more conclusive evidence of the contaminants and quality of the water. Several methods will be used to test the purity and qualities of […]

Multistep Reaction Sequence: Benzaldehyde to Benzilic Acid

Seth Dingas* and Jakkrit Suriboot ABSTRACT Benzilic acid was synthesized through a multistep reaction from the starting material of benzaldehyde and through the formations of benzoin and benzil.  The first reaction produced benzoin by using the thiamine hydrochloride catalyst, followed by an oxidation reaction to produce benzil, and a rearrangement to synthesize benzilic acid.  By utilizing crystallization, pure solid products of each step were collected and analyzed through IR, NMR spectroscopy, and other physical properties. Introduction Multistep synthesis reactions involve […]