Pharmacists, although not practicing chemists, often use skills and knowledge obtained in chemistry courses that are essential for success in their profession. This is especially apparent when preparing prescriptions for drugs that do not have a commercially available dosage form. Some well-publicized events indicate the potency of these drugs is…

A recent article by McCarty and Vitz "demonstrating that it is not true that pH = -log[H+]" is examined critically. Then, the focus shifts to underlying problems with the IUPAC definition of pH. It is shown how the potentiometric method can provide "estimates" of both the IUPAC-defined hydrogen activity "and" the hydrogen ion concentration, using…

The theoretical distributions of a limited amount of energy among small numbers of particles with discrete, evenly-spaced quantum levels are examined systematically. The average populations of energy states reveal the pattern of Pascal's triangle. An exact formula for the probability that a particle will be in any given energy state is derived.…

Inexpensive electrodes for the measurement of pH have been constructed using the ionophore tribenzylamine for sensing H[superscript +] concentrations. Both traditional liquid-membrane electrodes and coated-wire electrodes have been constructed and studied, and both exhibit linear, nearly Nernstian responses to changes in pH. Measurements of pH…

The concept of a positive hydrogen entity, later called the hydrogen ion and proton, seems to have started with Theodor von Grotthuss in 1805. The conception proposed by von Grotthuss has evolved via the works of many scientists; especially the contributions of Justus Liebig, Svante Arrhenius, S. P. L. Sorensen, I. M. Kolthoff, and R. P. Bell.…

The combination of reverse iontophoresis and flame photometry provides an engaging analytical experiment that gives first-year undergraduate students a flavor of modern drug delivery and analyte extraction techniques while reinforcing core analytical concepts. The experiment provides a highly visual demonstration of the iontophoresis technique and…

Differential scanning calorimetry analyses of two easily prepared polymorphs of acetaminophen (also known as paracetamol) are recorded. The density of the forms can be found in the literature. Rules for heats of transition, heats of fusion, and density, as well as methods for determining the solid-solid transition temperature between the forms,…

Kinetic study on the hydrolysis of diphenylbromomethane does not provide clear-cut evidence for the mechanism of the reaction. The reduction in the rate of the reaction by added bromide ions suggested that the reaction took place by a S[subscript N]1 mechanism. A more detailed study of this common-ion effect, using conductivity to measure the rate…

The inclusion of the history of science in science curricula--and specially, in the curricula of science teachers--is a trend that has been followed in several countries. The reasons advanced for the study of the history of science are manifold. This paper presents a case study in the history of chemistry, on the early developments of John…

Fill an ordinary latex balloon with helium gas and you know what to expect. Over the next day or two the volume will decrease noticeably as helium escapes from the balloon. So what happens when a latex balloon is filled with carbon dioxide gas? Surprisingly, carbon dioxide balloons deflate at rates as much as an order of magnitude faster than…

This paper explores the occurrence of conceptual incoherence in upper secondary school textbooks resulting from the use of multiple historical models. Swedish biology and chemistry textbooks, as well as a selection of books from English speaking countries, were examined. The purpose of the study was to identify which models are used to represent…

This research aims to investigate the influence of conceptual change texts on students' understanding and misconceptions related to the subject of alkenes. For this, nine conceptual change texts were developed by considering students' misconceptions and learning difficulties regarding alkenes. The participants of this study consist of 63 second…

This study focuses on using wikis as a learning environment, as part of a professional development program for chemistry teacher leaders. The study was performed in Israel and involved 20 chemistry teachers. One goal was to investigate how using wiki may promote effective science teacher professional development. Various aspects of the teachers'…

In classrooms, science is usually taught within the cognitive domain while the psychomotor learning domain is achieved through performing science experiments in the laboratory. Although students attend civic and moral education and pastoral care classes where values and life skills are often taught directly, learning experiences in most school…

This paper presents a cross-level study of German student teachers' beliefs about teaching and learning chemistry. It covers different stages of their teacher training program. The study is based upon drawings of teaching situations, which were analyzed using an evaluation pattern developed using grounded theory. The qualitative scales analyze…