Rate Law Determination of Everyday Processes

Abstract

In this experiment, students determined whether burning a birthday candle and flipping pennies are consistent with zero-, first-, or second-order rate laws. Students collected time-dependent data for the candle's mass or the number of pennies remaining (amount) and plotted curves of amount versus time, ln(amount) versus time, and amount−1 versus time. The linear plot of mass versus time indicates the candle experiment is consistent with a zero-order rate law, while the linear plot of ln(pennies) versus time indicates the penny experiment is consistent with a first-order rate law. Numerical values for the rate constants were determined from the slopes of the linear plots.

Flipping Pennies and Burning Candles: Adventures in Kinetics

“…The most linear graph determined the reaction order. It has been previously established that the penny flipping experiment is consistent with first-order reactions (1,2) and the candle experiment is consistent with zeroth-order reactions (1,(3)(4).…”

“…This Activity is an adaptation of a 2002 Journal of Chemical Education experiment (1) in which students plotted data in three graphs: amount versus time (linear for a zeroth-order process), ln [amount] versus time (linear for a first-order process), and amount -1 versus time (linear for a second-order process). The most linear graph determined the reaction order.…”

Zero-Order Chemical Kinetics as a Context To Investigate Student Understanding of Catalysts and Half-Life

“…Chemical kinetics is an understudied context within Chemical Education Research (CER), with the subject of zero-order systems even less represented among the literature. , Previous work involves an effort to provide analogies to help explain zero-order reactions , and the development of laboratory experiments that discuss zero-order reactions, − but CER related to zero-order reactions plays a minor role in larger projects centered more generally on chemical kinetics. − Furthermore, there is a need to explore research contexts that involve interdisciplinary content and participants from upper-level courses. , In this article, we discuss trends noted among general chemistry and upper-level students as they worked through an interview prompt about the half-life for a zero-order reaction that occurred by way of catalysis. Analysis was guided by the following research questions: How do students reason about zero-order systems? How do students reason about catalysts and half-lives? …”

Visualizing the Transition State: A Hands-on Approach to the Arrhenius Equation

“…A variety of methods including playing games, flipping pennies, and rolling dice have been used to model chemical reaction mechanisms, radioactive decay, and transition state theory for instructional purposes (1)(2)(3)(4)(5). Using games to model molecular behavior is a powerful teaching tool that gives students hands-on experience with the stochastic nature of individual atoms undergoing decay or specific molecules reacting.…”