Multicomponent solution calculations can be complicated for students and practiced chemists alike. This article describes how to simplify the calculations by representing a solution's composition as a point in a "concentration space," whose axes are the concentrations of each solute. The graphical representation of mixing processes in a…

In this laboratory activity, students were tasked with determining the heat of combustion for each of three common sugar substitutes: saccharin, aspartame, and sucralose. The heats of combustion were determined via three different methods: bomb calorimetry, heats of formation derived from semiempirical calculations, and tabulated average bond…

Chemometric techniques such as partial least-squares (PLS) regression have been applied with huge success to a wide array of chemical problems including multicomponent analysis of analytes in complex mixtures. Despite this, there are few examples of laboratory pedagogical exercises that involve students in the acquisition of chemical data from…

Reverse transcription quantitative polymerase chain reaction (RT-qPCR) is widely used in diagnosis and research to determine specific mRNA expressions in cells. As RT-qPCR applications increase, it is necessary to provide undergraduates hands-on experience of this modern technique. Here, we report a 3-week laboratory exercise using RT-qPCR to…

Raman spectroscopy is a powerful experimental technique, yet it is often missing from the undergraduate physical chemistry laboratory curriculum. Tetrachloromethane (CCl[subscript 4]) is the ideal molecule for an introductory vibrational spectroscopy experiment and the symmetric stretch vibration contains fine structure due to isotopic variations…

In these two classroom demonstrations, students observe the reaction between H[subscript 2] gas and Pd foil. In the first demonstration, hydrogen and palladium combine within one minute at 1 atm and room temperature to yield the non-stoichiometric, interstitial hydride with formula close to the maximum known value, PdH[subscript 0.7]. In the…

The aim of this experiment is to study and calculate the kinetic constant of a Heck reaction: the arylation of but-3-en-2-ol by iodobenzene catalyzed by palladium acetate in presence of triethylamine in DMF. The reaction leads to a mixture of two ketones. Students use GC analysis to quantify reagents and products of reaction. They control the…

A laboratory experiment is presented in which the freezing point depression is analyzed using milk as solution. The nature of milk as a mixture of different solutes makes it a suitable probe to learn about colligative properties. The first part of the experiment illustrates the analytical use of freezing point measurements to control milk quality,…

A three-point linkage system in tomatoes is used to explain concepts of gene mapping, linking and statistical analysis. The system is designed for teaching the effective use of statistics, and the power of genetic analysis from statistical analysis of phenotypic ratios. (Author/SA)

Describes a simple, inexpensive experiment in which students determine the heats of combustion of common solid, liquid, and gaseous fuels. The experimental apparatus, procedures, calculations and results are discussed. (CW)

Errors found in a common physics experiment to measure acceleration resulting from gravity using a linear air track are investigated. Glider position at release and initial velocity are shown to be sources of systematic error. (CW)

Describes a circuit by which capacitance and the dielectric constant can be measured. Shows the circuit diagram and the method to calculate these constants. (YP)