When FT-NMR is used to collect data without a sufficient delay time between subsequent pulses, the integrated area under certain peaks may result in a lower value than should be observed under appropriate conditions. This discrepancy in integration may deceive the inexperienced eye and consequently can lead to a wrong assignment of the NMR…

Waste newspaper is pulped with acid and its cellulose is hydrolyzed. The resulting glucose syrup is fermented with yeast and distilled to give ethanol. The experiment highlights the potential of applied chemistry to confront problems of economic importance, that is, the effective utilization of biomass to reduce dependence on non-renewable…

Treatment of phenylacetic acid with 90% HNO[subscript 3] yields a product, I, whose observed melting point is 175-179 degrees C and whose equivalent weight is approximately 226 grams. Treatment of phenylacetic acid with 70% HNO[subscript 3] yields a product, II, whose observed melting point is 106-111 degrees C and whose equivalent weight is…

A simple procedure for determining the zinc composition of U.S. pennies is described. The penny zinc core is dissolved in acid and the evolved hydrogen gas is collected by water displacement.

Every day, tens of thousands of chemists use analytical atomic spectroscopy in their work, often without knowledge of possible interferences. We present a unique approach to study these interferences by using modern response surface methods to visualize an interference in which aluminum depresses the calcium atomic absorption signal. Calcium…

In this experiment the carotenoid bixin is isolated from annatto ("Bixa orellana") seeds using column chromatography. The experiment has several key advantages over previous pigment separation experiments. First, unlike other experiments significant quantities of the carotenoid (typically 20 to 25 mg) can be isolated from small quantities of plant…

The iodochlorination of styrene, involving the addition of iodine monochloride to styrene, followed by the sodium methoxide-initiated dehydrohalogenation of the product results in a variable mixture of substituted styrenes by way of various substitution and elimination reaction mechanisms. As a result individual results are obtained for each…

The fundamental and overtone vibrational absorption spectroscopy of the C-H unit in CHCl[subscript 3] is measured for transitions from the v = 0 energy level to v = 1 through v = 5 energy levels. The energies of the transitions exhibit a linearly-decreasing spacing between adjacent vibrational levels as the vibrational quantum number increases.…

An educational set-up for cosmic ray physics experiments is described. The detector is based on scintillator tiles with a readout through metal resistor semiconductor (MRS) avalanche photo diode (APD) arrays. Typical measurements of the cosmic angular distribution at sea level and a study of the East-West asymmetry obtained by such a device are…

Comparison of the thermodynamic entropy with Boltzmann's principle shows that under conditions of constant volume the total number of arrangements in a simple thermodynamic system with temperature-independent constant-volume heat capacity, C, is T[superscript C/k]. A physical interpretation of this function is given for three such systems: an…

Not so long ago a new observation about rolling motion was described: for a rolling wheel, there is a set of points with instantaneous velocities directed at or away from the centre of the wheel; these points form a circle whose diameter connects the centre of the wheel to the wheel's point of contact with the ground (Sharma 1996 "Eur. J. Phys."…

We describe a simple and very inexpensive undergraduate laboratory experiment for fast determination of Young's modulus at moderate temperatures with the aid of a force sensor. A strip-shaped specimen rigidly bolted to the force sensor forms a clamped-free cantilever beam. Placed in a furnace, it is subjected to free-bending vibrations followed by…

We describe the construction and operation of three low-cost schlieren imaging systems that can be fabricated using surplus optics and 80/20, an aluminium extrusion based construction system. Each system has a different optical configuration. The low cost and ease of construction makes these systems highly suitable for high-school and…

Exact closed-form solutions of the time-dependent Schrodinger equation are obtained, describing the propagation of wavepackets in the neighbourhood of a potential. Examples given include zero reflection, total reflection and partial reflection of the wavepacket, for the sech[superscript 2]x/a, 1/x[superscript 2] and delta(x) potentials,…

The Laplace equation has applications in several fields of physics, and problems involving this equation serve as paradigms for boundary value problems. In the case of the Laplace equation in a disc there is a well-known explicit formula for the solution: Poisson's integral. We show how one can derive this formula, and in addition two equivalent…