As the need for alternative energy becomes increasingly important, energy research and related industries are rapidly expanding. This lab incorporates current energy-storage research into a second-year lab that instills real-world, industry-relevant knowledge and skills while teaching and reinforcing physical-chemistry concepts. A manganese oxide electrode, aqueous-Na2SO4-electrolyte supercapacitor system is used because it has no air or water sensitivity, unlike most battery technologies, so it is easy to implement in an undergraduate-lab setting. Manganese oxide is an increasingly popular supercapacitor material, and this lab introduces the concept of pseudocapacitance, in which current flows while still being governed by the Nernst equation (i.e., at equilibrium). Students conduct realistic and industrially relevant electrochemical experiments; they electrodeposit manganese oxide films and test them using cyclic voltammetry. Students compare the manganese oxide results to those from a nonpseudocapacitive system (i.e., a poor supercapacitor). In doing so, they learn the concepts of charge storage and energy and power (and their important differences), while reinforcing the physical-chemistry topics of thermodynamics and kinetics, all within a frame of familiar electrochemical knowledge (i.e., the Nernst equation). This lab can be completed in one 4 h laboratory period or in a 3 h period if the solutions are provided to the students or they prepare them a week in advance. Student interest and engagement is heightened by their being able to see the real-world applications and skills.

We describe a laboratory experiment that serves as an introduction to solid-state and materials science, a topic that requires additional attention in the undergraduate chemistry laboratory curriculum. The experiment illustrates the longrange translational order, crystal growth, and the macroscopic manifestations of that order. This is demonstrated through the preparation and characterization of large, well-formed bismuth crystals, an aesthetically pleasing product. The characterization of the grown bismuth crystals involves determination of melting point and enthalpy of fusion via differential scanning calorimetry. The temperature dependence of the electrical resistance of grown bismuth crystals is also measured. Students are encouraged to consider the effect of metallic bonding interactions on the melting of the crystal samples and on their ability to conduct electricity. Students also analyze how the impurities influence the melting point and the electrical properties. The experiment is suitable for use in the third-or fourth-year undergraduate laboratory and is performed by students in one four-hour session. The experiment could be adapted to two laboratory sessions, with the first two-hour session covering crystal growth, and the second two-hour session focused on thermal and electrical characterization.

The design and construction of an apparatus to measure the optical birefringence of a liquid crystal is described. The instrument also includes temperature control and monitoring circuitry to allow for the measurement of the nematic-to-isotropic phase transition temperature. An important feature of this design is that the students are able to build the optical bench section of the instrument from a kit of parts supplied. The electronics instrumentation for the illuminator, photometer, and temperature controller functions are all low-cost designs using common components, yet provide more than adequate accuracy for the measurements required. The entire instrument cost is $430, an estimated cost reduction of approximately $3000 compared to the design previously proposed by Waclawik et al. This instrumentation is suitable for second or third-year undergraduate students in materials science or physical chemistry courses.

The pyrolysis of ethane was performed in tubular reactors at temperatures from 1110 K to 1220 K, at pressures from 40 kPa to 80 kPa and at residence times from 1.4 s to 58 s. The formation of a fog was monitored using laser extinction. The boundaries of the regime of time, temperature and pressure in which a condensed phase was formed were delineated. Five simple analytical models were derived in order to analyze the kinetics of formation of this phase. The parameters in the models were fitted to the experimental data and were compared to the predictions of the kinetic theory. The most successful model involved a steady formation of precursors until a critical pressure was reached. Nucleation then occurred rapidly, followed by a steady growth of the volume of the particles. The temperature dependence of the inverse of the incubation period was determined to be In[(theta/s)(-1))] = -(200 +/- 30) kJ mol(-1)/RT + (20 +/- 4). The rate of particle growth was proportional to the square of the reactant pressure and followed the following Arrhenius expression: In[omega/s(-1)] = -(420 +/- 40) kJ mol(-1)/RT + (39 +/- 4). According to this model the heat of vaporization of the droplets was (210 +/- 50) kJ mol(-1). This was consistent with condensation of polynuclear aromatic hydrocarbons having molecular weights of about (460 +/- 110) g mol(-1). At longer residence times the attenuation of the laser beam reached a plateau. This was interpreted in terms of a decline in the rate of fog formation or in terms of the removal of droplets by deposition on the reactor surface.

In this supplement to our second-year supercapacitor lab (Bringing Real-World Energy-Storage Research into a Second-Year Physical-Chemistry Lab Using a MnO 2 -Based Supercapacitor. J. Chem. Educ. 2018, 95 (11), 2028− 2033), we incorporate a color indicator as indirect evidence for the manganese oxide's pseudocapacitive reaction (MnO 2 + H + + e − ⇌ MnOOH). Using the evidence of pH changes (the methyl red goes from light yellow to red during an oxidative potential hold), students can make the link between oxidation state changes and the applied potential of the electrochemical experiment. Herein, we optimize the indicator concentration and electrochemical parameters to ensure the color changes are evident. Optimal responses arise when 15 μM methyl red is coupled with a 2 min, 0.8 V potentiostatic hold.