A functionalized fiber (PAN[subscript ADMAP]F) was synthesized by immobilizing "N,N'"-dimethyl-"N"-(4-pyridinyl)-1,3-propanediamine (ADMAP, a DMAP analogue) onto the surface of polyacrylonitrile fibers (PANF). The structure and morphology of the functionalized fibers were characterized by Fourier transform infrared…

When the thermal expansion of water is discussed in school or university lessons, functional relationships are often inferred without considering measurement uncertainties. Moreover, in some learning materials, the goal of experimentation and the experimental setup do not match. This creates the wrong picture of scientific practice. In this…

Since at least the 1960s, organic chemistry textbooks have featured pK[subscript a] tables for organic acids that include values for H[subscript 2]O and H[subscript 3]O[superscript +] (15.74 and -1.74, respectively) that are thermodynamically and chemically indefensible. Here we trace this error back to Brønsted's early contributions in the 1920s…

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…

A simple experiment to reveal the dimension of the pore space in sponges is proposed. This experiment is suitable for the first year of a physics or engineering course. The calculated dimension of the void space in a sponge of density 16 mg cm[superscript -3] was 2.948 [plus or minus] 0.008. (Contains 2 figures.)

Sulfate reducing bacteria have been shown to be effective at treating acid mine drainage through sulfide production and subsequent precipitation of metal sulfides. In this laboratory experiment for undergraduate environmental chemistry courses, students design and implement a set of bioreactors to remediate acid mine drainage and explain observed…

The determination of sulfate concentration in water by indirect EDTA titration is an instructive experiment that is easily implemented in an analytical chemistry laboratory course. A water sample is treated with excess barium chloride to precipitate sulfate ions as BaSO[subscript 4](s). The unprecipitated barium ions are then titrated with EDTA.…

A simple method of casting with a Ti[O[subscript]2]/polyvinylchloride (PVC) composite layer was used to describe the behavior of coated electrodes. The system demonstrated that even with low energy light sources, an enhancement of the oxidation efficiency is possible.

Skepticism is one of the cornerstones of scientific learning. Some pseudosciences in domains such as astronomy or pharmacy use a host of issues in everyday life as pretexts for work in the classroom (e.g., astrology) or laboratory (e.g., homeopathy). Chemistry also offers opportunities to promote skeptical thinking in students. Commercial devices…

On equilibrium properties of aqueous solutions of sulfuric acid, Julius Thomsen has marked that the heat evolved on diluting liquid sulfuric acid with water is a continuous function of the water used, and excluded absolutely the acceptance of definite hydrates as existing in the solution. Information about thermochemical measurement, a discussion…