Category : Natural Sciences

Quantum Dot Nanocrystals Experiment

By: David Gould Partners: Alaina Nunn, Stephanie Bolini CHEM 322L | February 17, 2014 – Quantum Dot Abstract: This experiment works to determine how quantum dots are prepared in a laboratory setting, and their analysis spectroscopically. With uses as semiconductors in the electronic industry, quantum dots perform faster due to their small size. Being so small these nanoparticles do not obey the laws of classical physics and must be studied in the quantum realm. Various quantum mechanical models are discussed and it […]

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 […]

High-Throughput Experimentation: Palladium-Catalyzed Suzuki-Miyaura Cross-Coupling

By: Jingyuan Ma Introduction This lab introduced techniques used in the Penn/Merck High-Throughput Experimentation Center. The Suzuki-Miyaura reaction was implemented using 4 reagents, an assigned inorganic base, an assigned solvent, and pre-dosed phosphine ligands. TLC and HPLC were used to qualitatively analyze the reactivity trends of 24 reaction screens, which were all conducted under room temperature and controlled settings. The following overall reaction was conducted to catalyze sp2-sp2 carbon-carbon bonding through the use of a palladium catalyst: The following is […]


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 […]

The Diels-Alder Reaction

By: Kayla Powers and Jakkrit Suriboot Introduction Diels-Alder reactions are used for synthesizing new carbon-carbon bonds and more specifically, six-membered cyclic compounds. In addition, this reaction synthesizes compounds that are otherwise difficult to obtain, such as bridged bicyclic compounds.  A key characteristic of these reactions is their stereospecificity.  Based on the interaction between a conjugated diene and a dienophile, different stereoisomeric compounds are formed.   The Diels-Alder reaction is categorized as a pericyclic reaction, which involves the overlap of spatial orbitals […]

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 […]