To study the absorption of ultrasound in plexiglas we propose to use gadgets that are available to each student: an ultrasound humidifier, a liquid crystal display of a pad, a polaroid analyzer, a digital camera, a multimeter with thermocouple, and a stopwatch. These devices allow us to visualize a region in plexiglas where ultrasound is absorbed…

Although teaching laboratories offer students the opportunity to act and think like chemists, in many cases students simply follow written procedures to generate predetermined outcomes. In recent years, there has been a movement toward inquiry-, problem-, and discovery-based learning. In a similar vein, the first-semester introductory organic…

Newton's law of cooling describes an object whose temperature decreases exponentially with time. Because of its many applications, it is a frequent topic of introductory physics labs. In this article, I describe an experiment designed for the freshman year algebra-based physics course that applies this law to answering the question, "Why…

"N"-Formamides are important intermediates in the synthesis of many pharmacologically active compounds and are used as protecting groups for amines or as catalysts in different reactions. The current "N"-formylation experiment is designed as a part of an introductory organic chemistry course for undergraduate students. The…

Enzyme kinetics is an essential topic in undergraduate Biochemistry courses. A laboratory work that covers the principal basic concepts of enzyme kinetics in steady state is presented. The alkaline phosphatase catalyzed reaction of phenyl-phosphate hydrolysis was studied as a model. The laboratory experience was designed to reinforce the concepts…

We describe a 2 h general-chemistry experiment that introduces college students not only to the concepts, synthesis, and applications of nanomaterials at an early stage but also the use of a spectrophotometer for quantification and unknown determination based on Beer's Law. The procedure involves students (1) preparing a nanocomposite by…

A Microsoft Excel workbook has been developed to simplify the quantitative analysis of experimentally measured titration curves for diprotic and triprotic amino acids such as glycine, arginine, histidine, and glutamate. Students perform the titration, enter the data into the worksheet, and manually adjust the resulting pK[subscript a] values to…

Einstein's relation between mass and energy is perhaps the most famous equation of Physics. Despite its simplicity, the meaning of E[subscript 0] = mc[superscript 2] is not easy to grasp. Furthermore, its traditional derivations rely either on the integral of "momentum," on properties of electromagnetic radiation, or even on the…

There is an increasing need for fundamental electrochemistry concepts to be taught in the undergraduate curriculum, given the broad applicability of electrochemical technologies in addressing a wide range of global issues from critical energy shortages to real-time medical diagnostics. However, many electrochemical concepts are often taught in…

Thin-layer chromatography, which involves the movement of dyes along a silica-coated plate, is used to observe the progress of chemical reactions and to separate mixtures. We took advantage of this phenomenon to devise a method for generating patterns in the shape of numbers with dots (dot matrix). We prepared the azo dyes necessary for generating…

In this laboratory teaching experiment, commercial cannabis oils were analyzed by undergraduate organic chemistry students using gas chromatography-mass spectrometry (GC-MS) to investigate three isomeric cannabinoids commonly found in cannabis products: cannabidiol (CBD), [delta][superscript 9]-tetrahydrocannabinol ([delta][superscript 9]-THC),…

Thermodynamic characterization of micelle formation from an ionic surfactant in aqueous solutions is a classic experiment in physical chemistry. The critical micelle concentration (CMC) and the degree of micelle ionization ([alpha)] can be directly obtained by conductimetry, then thermodynamic parameters ([delta]G[subscript m][superscript o],…

The free radical chlorination of an alkane experiment is often used in the undergraduate laboratory curriculum to introduce students to the free radical mechanism, substituent effects, intermediate stability, and the relative reactivity of radicals. In this experiment, students monochlorinate multiple alkanes and analyze the reaction mixture using…

Inductively coupled plasma optical emission spectroscopy (ICP-OES) is one of the most commonly used analytical techniques for the measurement of metals in environmental matrices. However, one of the drawbacks of ICP-OES is interference, viz., spectral and nonspectral (due to transport effects) interference. In this simple laboratory experiment,…

Keto-enol tautomerism is a special example of structural isomerism. In this experiment, 6-chlorofulvene is predominantly yielded during the chlorination reaction of 6'-hydroxyfulvene with POCl[subscript 3] in the presence of DMF. The high regioselectivity of this reaction is dominated by intramolecular hydrogen-bonding and steric hindrance,…