The Beer-Lambert law is a core spectroscopic relationship widely used across the undergraduate chemistry curriculum and beyond. The derivation of this model is a common topic for upper-level chemistry courses. But, du...
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The Beer-Lambert law is a core spectroscopic relationship widely used across the undergraduate chemistry curriculum and beyond. The derivation of this model is a common topic for upper-level chemistry courses. But, due to its abstract nature, this derivation can often seem like a mathematical exercise detached from the molecular origins of absorption. Here, we present an activity centered around a simulation of absorption using spheres and cylinders. By interacting with variables in the simulation in a guided-inquiry format, students can connect the submicroscopic interactions between photons and molecules with the mathematical relationships that ultimately give rise to the Beer - Lambert Law. The activity presented here was implemented as a virtual lab for a cohort of analytical chemistry students during the COVID-19 pandemic. Our evaluation of student responses shows the promise of this activity for encouraging students to engage in the scientific practice of modeling the submicroscopic nature of absorption to understand the development of Beer's Law. In addition, we discuss how patterns observed in student responses have informed improvements to the activity for future implementations and identify some additional learning contexts to which the interactive simulation can be applied.
A multistep synthesis of quinolone antibiotic analogues was developed as a laboratory experiment for intermediate/advanced undergraduate students. Students can synthesize a range of desfluoroenoxacin analogues via a f...
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A multistep synthesis of quinolone antibiotic analogues was developed as a laboratory experiment for intermediate/advanced undergraduate students. Students can synthesize a range of desfluoroenoxacin analogues via a five-step sequence. The experiment includes a range of key practical laboratory techniques including thin-layer chromatography (TLC), liquid-liquid extraction, trituration, recrystallization, and the characterization of compounds by IR and NMR spectroscopy. The experiment provides an opportunity for students to carry out fundamental organic chemistry transformations from the curriculum such as the preparation of acyl chlorides, 1,4-conjugate addition-elimination, heterocycle synthesis, nucleophilic aromatic substitution, and ester hydrolysis. The five-step sequence does not require column chromatography and can be adapted to a range of laboratory settings.
Students' inaccurate ideas about what is represented by chemical equations and concepts underlying stoichiometry are well documented;however, there are few classroom ready instructional solutions to help students ...
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Students' inaccurate ideas about what is represented by chemical equations and concepts underlying stoichiometry are well documented;however, there are few classroom ready instructional solutions to help students build scientifically accurate, ideas about these topics central to learning chemistry. An intervention (two inquiry-based activities) was developed, piloted, and evaluated with common misconceptions in mind. The intervention was carried out in five sections of a high school chemistry class at a technical career campus, and pre/posttest data using a published instrument were collected to evaluate the intervention's effectiveness in building accurate stoichiometric concepts. Statistically significant growth with a large effect size occurred from pre to posttest demonstrating that the intervention improved conceptual understanding even though there were variations in the intervention delivery, as well as small differences detected between 11th and 12th grade student performance. The study, an action research project carried out by a teacher enrolled in a long-term professional development program, has implications for the value of rigorous materials design and evaluation framed by the chemistry education research literature. Study replication in other classroom contexts would be useful in further validating the learning outcomes of the activities. For practitioners, the activities studied here are free and available online for classroom use.
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