Tag Archives | Thomas Kuntzleman

Kuntzleman, Thomas S., David Sellers, and Rachel Hoffmeyer. “‘ Having a Ball with Chemistry’: More Things to Try.” Journal of Chemical Education 85, no. 11 (2008): 1478.

Abstract: A short outreach activity is described in which students test the rebound properties of superballs, racquetballs, “happy” balls and “sad balls” at many temperatures. After conducting the experiment, students use the test results to estimate the glass transition temperature of the elastic polymer that comprises each ball. The activity is used to segue into the classic demonstration of dipping a racquetball in liquid nitrogen and watching it shatter when thrown against a hard surface. In addition, students are encouraged to relate the results of the experiment to the importance of warming up muscles before exercise.

Swanson, Matthew S., Deborah K. Sayers, and Thomas S. Kuntzleman. “Visualizing the Transition State: A Hands-on Approach to the Arrhenius Equation.” Journal of Chemical Education 84, no. 11 (2007): 1776.

Abstract: An exercise is presented in which the kinetics of the irreversible “reaction” of pennies in the heads-up state to pennies in the tails-up state is simulated by a hands-on, Monte Carlo approach. In addition, the exercise incorporates a second simulation in which the irreversible “reaction” of dice with a red face uppermost to a blue face uppermost is conducted. The transition states of the reactions are assumed to be a penny that is in the process of being flipped or a die in the process of being rolled, respectively. Data collected by students who perform these simulations show that both “reactions” follow first-order decay kinetics. Arrhenius plots from these data yield activation energies comparable to assigned values and pre-exponential factors close to what would be expected based on the probability of a “reactant” achieving the correct orientation for conversion into “product”. A comparison of the values obtained for the pre-exponential factors for the different simulations allows students to semi-quantitatively discuss the orientational requirement that is contained within this factor.