AP Chemistry: Chemical Kinetics
Task
Task Purpose Chemical kinetics relies heavily on performing experiments and subsequently analyzing data to make conclusions. This project allows students to explore several methods of data analysis employed in chemical kinetics in a sequence of steps. Narrative In this task, students: Interpret data outlining the variation of a specific reactant over time. Create a log of reactant concentration over time to determine the order of the reaction with respect to the reaction, and find the rate constant of the reaction. Fit function to the concentration change over time to find half life of a reactant, and compare the obtained value to that obtained using the formula relating reaction rate and half life. Plot a graph of reaction rate vs. temperature to find the activation energy of the reaction. Standard Overall, the task definitively achieves the following goals of the AP Chemistry curriculum: 5.3.A Identify the rate law expression of a chemical reaction using data that show how the concentrations of reaction species change over time. 5.6.A Represent the activation energy and overall energy change in an elementary reaction using a reaction energy profile. How Tuva Enhances the Lesson By allowing students to make graphs, Tuva enables them to perform the mathematical routines commonly used in a chemical kinetics class. It also allows students to look behind the scenes to understand how the graphs are constructed and how manipulating collected data supports the sensemaking they are expected to do.
Carbon's compounds impact our lives in a variety of ways. Consider a simple molecule like chloromethane, or $$CH_{3}Cl$$. In the early days of refrigeration, chloromethane was used as a refrigerant. It was banned as a refrigerant in the 1930s after we learned about its devastating health impacts. In industry, chloromethane is still used to enable polymerization and to produce methylamine, an ingredient in pharmaceuticals, dyes, and agrochemicals. Chemists study chemical kinetics to figure out how reactions happen and how fast they occur, which helps them control reactions for useful purposes. By analyzing reaction mechanisms, chemists can understand how chloromethane behaves, predict harmful outcomes, and make decisions that reduce risk to people and the environment. Given chloromethane's potential harm, today we will analyze data about its role in a chemical reaction and work to identify the reaction mechanism.
Topics and standards: Grades 9-12, AP Sciences, High School Science Collections, AP Chemistry, Assessment