This paper, for chemistry teachers who have beginning students, computers, and spreadsheets, presents tables of titration data simulated using the program EQUIL. Instructors are invited to give students the titration data to enter into their spreadsheets, have them plot it in several ways, and produce an assortment of graphs. In the process, they will discover many things about pH,. the taking of derivatives, buffer capacity, and the way buffers behave upon dilution. These resulting plots show why there is pseudobuffering at high and low pH values, and show the equilibrium buffering maximum at the pKa or pKb of the electrolyte species. A convenient definition of buffer capacity with respect to dilution is beta dil, where beta dil = d(-log[conc]/d(pH). This definition has the advantage of being an intensive property of the solution, and also of being large for equilibrium buffer solutions undergoing dilution.

Laser-induced fluorescence detection of the OH product following the reaction 0(3Py) + SiH4 -( 2 ) + SiH3 reveals a strong vibrational population inversion, P(l)/P{0) = 3.4 ± 0.4. The rotational distribution of the major product in v" = 1 is thermal with Trot = 600 ± 20 K. The product distribution of OH in " = 0 cannot be simply characterized in terms of a temperature, nor does the population ratio for the doublet components provide unambiguous evidence concerning the production mechanism, but it clearly differs from that responsible for production of the vibrationally excited products.

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A persistent concern within physics education is students' apparent failure to check the reasonableness of their answers. In an effort to better understand how students' capacity for checking solutions develops, this paper examines data on solution checking in an upper-level undergraduate electricity and magnetism course. All students demonstrated the ability to check answers in multiple ways, but showed variability in how they chose to do so, with checking units the most easily activated check, and numerical values strikingly underutilized.