A modified laboratory experiment for undergraduate students is presented to evaluate the effects of the ionic strength, "I", on the equilibrium concentration quotient, K[subscript c], of the acid-base indicator bromcresol green (BCG). The two-step deprotonation of the acidic form of the dye (sultone form), as it is dissolved in water, yields…

During the years 1873-1879, J. Willard Gibbs published his now-famous set of articles that form the basis of the current perspective on chemical thermodynamics. The second article of this series, "A Method of Geometrical Representation of the Thermodynamic Properties of Substances by Means of Surfaces," published in 1873, is particularly notable…

We have analytically explored the thermodynamics of free Bose and Fermi gases for the entire range of temperature, and have extended the same for harmonically trapped cases. We have obtained approximate chemical potentials for the quantum gases in closed forms of temperature so that the thermodynamic properties of the quantum gases become…

Acid-base equilibrium is one of the most important and most challenging topics in a typical general chemistry course. This article introduces an alternative to the algebraic approach generally used in textbooks, the graphical log "C" method. Log "C" diagrams provide conceptual insight into the behavior of aqueous acid-base systems and allow…

The spectra of some chemical elements display intense infrared (IR) lines that can be used more effectively than the ones in the visible region for identification purposes. A simple setup, based on the IR sensitivity of a handycam in nightshot mode, is described to record the visible as well as the IR spectra from decorative bulbs or salts on the…

To provide tools for programmatic assessment related to the use of ACS Exams in undergraduate chemistry courses, the ACS Exams Institute has built a content map that applies to the entire undergraduate curriculum. At the top two levels, the grain size of the content classification is large and spans the entire undergraduate curriculum. At the…

In the course of the 18th century a new type of scientifically educated functional elites developed, who were trained to administer mines. The educational project that led to the formation of a corps of mining engineers was part of a programme of administrative and economic reforms that led to a new configuration of bonds between state, economy…

Noticing the presence of colourless crystals in a glass of white wine was the starting point for some simple experiments to identify their chemical nature. The author did not succeed in identifying the chemical, but learned about the presence of an acid-base indicator. In retrospect, he was aware of the special chemical way he had considered the…

The goal of this study was to identify student misconceptions and difficulties in writing symbolic-level balanced equations for dissolving ionic compounds in water. A sample of 105 college students were asked to provide balanced equations for dissolving four ionic compounds in water. Another 37 college students participated in semi-structured…

Characterizing the modes of reasoning typically applied by students to solve different types of chemistry problems is of central importance for the design of instructional strategies that can better support their learning of specific content. Thus, the central goal of this study was to identify dominant modes of reasoning expressed by college…

Mathematical ability is a major contributory factor to the success of a student in any science course. This paper aims to determine the source of the difficulty that students often find when performing calculations in chemistry. Through the design and analysis of a set of chemistry questions and analogous mathematics questions, set in a Standard…

Previous research has reported that students commonly develop alternative conceptions in the core topic of chemical bonding. Research in England has reported that students there commonly demonstrate an alternative "molecular" conceptual framework for thinking about ionic bonding: in terms of the formation of molecule-like ions pairs…

Liquid carboxylic acids (or primary amines) with limited solubility in water are dissolved by addition of aqueous sodium hydroxide (or hydrochloric acid) on the stage of an overhead projector using simple glassware and very small quantities of chemicals. This effective and colorful demonstration can be used to accompany discussions of the…

As China's university enrollment has been rapidly expanding since 1999, along with a steady increase in graduate enrollment, graduate-level chemistry education is confronted with many challenges, such as how to enhance the connection between fundamental knowledge and advanced frontier knowledge, and how to encourage students to do self-directed…

The substitution of petroleum-based fuels with those from renewable sources has gained momentum worldwide. A UV-vis experiment for the quantitative analysis of biofuels (bioethanol or biodiesel) in (petroleum-based) diesel oil has been developed. Before the experiment, students were given a quiz on biofuels, and then they were asked to suggest a…