Resumen de Interactive Demonstrations for Mole Ratios and Limiting Reagents
The objective of this study was to develop interactive lecture demonstrations (ILD) based on conceptual-change learning theory. Experimental instruction was designed for an introductory chemistry course for nonmajors to address misconceptions related to mole ratios and limiting reagents. Students were asked a series of questions related to two chemical demonstrations via an electronic keypad system. Questions asked during the demonstrations included conceptual items, particulate items, and traditional textbook-style calculations. Results indicate that use of the ILDs decreased students' misconceptions and that they were a positive addition to the course. Students' understanding was determined via a pretest and posttest that included multiple-choice and free-response questions. Students showed significant improvement on the multiple-choice items after instruction. Evaluation of free-response items via a rubric indicated that participants understanding of stoichiometry increased. A large majority of student evaluations suggested that the interactive system had a positive effect on their learning.
