In this paper an experiment to study Planck's radiation law is presented. The spectra of a heated furnace and of a halogen lamp under various conditions were measured with a small USB grating spectrometer and fitted using Planck's law. The temperature determined from the fit was then compared with the results of comparative temperature…

In this article we examine cases of more classical and less classical nature compared to results found by quantum mechanics and attribute a form of Free Energy discontinuity for each case within a boundary layer. The concept of a boundary layer is broadened as to include areas of first or second variations of the Gibbs free energy. It is…

An alternative method of presenting the second law of thermodynamics in introductory courses is presented. The emphasis is on statistical approaches as developed by Atkins. This has the benefit of stressing the statistical nature of the law.

Scientific terms drawn from common language are often charged with suggestions that may even be inconsistent with their restricted scientific meaning, thus posing didactic problems. The (non-linear) historical journey of the word "pressure" is illustrated here through original quotations from Stevinus, Torricelli, Pascal, Boyle,…

The relationship between physics and mathematics is hardly ever presented with sufficient clarity to satisfy either physicists or mathematicians. It is a situation that often leads to misunderstandings that may spread quickly from teacher to student, such as the idea that mathematics is a mere instrument for the physicist. In this paper, we…

For physical measurements, the compositions of solutions, especially electrolyte solutions, are expressed in terms of molality rather than mole fractions. The development of the necessary thermodynamic equations directly in terms of molality is not common in textbooks, and the treatment in the literature is not very systematic. We develop a…

The thermodynamic properties of weak acid ionization reactions are determined. The thermodynamic properties are corresponding values of the absolute temperature (T), the weak acid equilibrium constant (K[subscript a]), the enthalpy of ionization (delta[subscript i]H[degrees]), and the entropy of ionization (delta[subscript i]S[degrees]). The…

In undergraduate chemical thermodynamics teachers often include equations and view manipulations of variables as understanding. Undergraduate students are often not able to describe the meaning of these equations. In chemistry, enthalpy and its change are introduced to describe some features of chemical reactions. In the process of measuring heat…

By growth in size and complexity (i.e., changing from more probable to less probable states), plants and animals appear to defy the second law of thermodynamics. The usual explanation describes the input of nutrient and sunlight energy into open thermodynamic systems. However, energy input alone does not address the ability to organize and create…

To help students make the connection between the concepts of heat conduction and convection to real-world phenomenon, we developed a combined experimental and computational module that can be incorporated into lecture or lab courses. The experimental system we present requires materials and apparatus that are readily accessible, and the procedure…

The Wittig reaction is one of the most useful reactions in organic chemistry. Despite its prominence early in the organic chemistry curriculum, the exact mechanism of this reaction is still under debate, and this controversy is often neglected in the classroom. Introducing a simple computational study of the Wittig reaction illustrates the…

An improved procedure for laboratory determination of the heat capacities of metals is described. The temperature of cold water is continuously recorded with a computer-interfaced temperature probe and the room temperature metal is added. The method is more accurate and faster than previous methods. It allows students to get accurate measurements…

An experiment is described that determines the activation energy (E[subscript a]) of the iodide-catalyzed decomposition reaction of hydrogen peroxide in a much more efficient manner than previously reported in the literature. Hydrogen peroxide, spontaneously or with a catalyst, decomposes to oxygen and water. Because the decomposition reaction is…

An update to the thermochromic cobalt(II) chloride equilibrium demonstration is described. Filter paper that has been saturated with aqueous cobalt(II) chloride is heated for seconds in a microwave oven, producing a color change. The resulting pink and blue map is used to colorfully demonstrate Le Châtelier's principle and to illuminate the hot…

An analysis is presented of the experience and lessons learned of running a MOOC in introductory physical chemistry. The course was unique in allowing students to conduct experimental measurements using a virtual laboratory constructed using video and simulations. A breakdown of the student background and motivation for taking the course is…