General Chemistry Laboratory Curriculum Research Articles

Teaching Single Crystal X-ray Crystallography in the Undergraduate Classroom with Sugar and Epsom Salt

We developed a single crystal X-ray crystallography experiment based on the crystal structure of sucrose (table sugar), and a more challenging experiment using Epsom salt. Both crystals are readily available in X-ray quality crystalline form. In these experiments, students mounted a crystal on a MiTeGen loop and analyzed it using a Rigaku XtaLAB Mini diffractometer (built 2011). Students generated models of both compounds using CrysAlisPro, Olex2, SHELXT, and SHELXL. All aspects of this experiment use free software programs which have user-friendly interfaces. A step-by-step laboratory protocol for determining the structure of both compounds is included in the Supporting Information. These experiments were used in the Fall of 2019 at the Junior and the Senior level. In the Summer of 2020, a take-home version of the lab was created in response to the Novel 2019 Coronavirus (COVID-19) pandemic and implemented in the General Chemistry laboratory curriculum; this experiment was used for the duration of the 2020–2021 academic year. These experiments are suitable for all undergraduate experience levels.

Simple Approach to Incorporating Experimental Design into a General Chemistry Lab

In an idealized General Chemistry Laboratory curriculum, students would hone their experimental design ability with practice encouraged by laboratory exercises designed to be open-ended. However, traditional General Chemistry Laboratory courses often lack opportunities for students to design their own experiments, instead opting to provide students with predetermined protocols. In addition, introducing guided inquiry into a General Chemistry Laboratory is logistically challenging, often prohibiting implementation. Here, we present a method for converting a traditional “cookbook-style” laboratory curriculum into one that is more open-ended with opportunities for students to practice experimental design skills. Our approach involves developing clear learning objectives, evaluating the existing curriculum for alignment to those objectives and providing opportunities for incorporating experimental design, and revising existing protocols. These revisions adopted a two week model, following up a traditional cookbook-style exercise focused on teaching students a given technique with a second week where students designed their own experiments to answer an instructor-provided question situated in a real-world context. This design provided sufficient structure for students to learn basic chemistry laboratory techniques while also creating the opportunity for practicing science process skills such as experimental design. Students in a pilot group experiencing this revised curriculum reported greater increases in their confidence with experimental design than peers in the traditional curriculum. We propose that this model could be adopted by other institutions as a meaningful step toward fully open-ended laboratory courses while avoiding many of the associated challenges.

Implementing an Iterative and Collaborative Approach to Inclusive First-Semester General Chemistry Laboratory Redesign

General chemistry laboratory curriculum reform is underway at a midsized state university through a collaborative, inclusive, and iterative approach. Using a backward design approach, faculty collaborated to actualize a shared vision, define laboratory learning objectives, and outline considerations for inclusivity during summer workshops that guided the process of curriculum design. With support from an instructional designer from the Center for Innovative Teaching and Learning, as well as faculty development support through an HHMI Inclusive Excellence grant, the faculty have designed and implemented the new curriculum, assessed the implementation, and continue to make iterative change based on student data and reflection. The goal of this report is not to provide a new set of chemistry laboratories, rather, we share our framework to provide an example of how to implement a collaborative and inclusive laboratory redesign.

Developing a Green Chemistry Focused General Chemistry Laboratory Curriculum: What Do Students Understand and Value about Green Chemistry?

Over the past several decades, green chemistry has gained prominence in chemistry education. However, the development of green chemistry curricula has not reached all levels of education equally, f...

The Evaluation of a Hybrid, General Chemistry Laboratory Curriculum: Impact on Students’ Cognitive, Affective, and Psychomotor Learning

The laboratory has occupied an important place in the general chemistry curriculum for well over a century, despite the fact that many have voiced concern about its value and utility. In an effort to potentially increase capacity in our general chemistry courses, we developed and implemented a hybrid laboratory curriculum that consisted of alternating face-to-face and virtual laboratory experiments. This study sought to better understand the impact that this hybrid approach had on students’ cognitive, affective, and psychomotor learning. The results suggest that students taught using the hybrid approach developed similar cognitive and psychomotor skills in comparison to students taught using a traditional laboratory curriculum; however, their affective outlook toward chemistry was significantly lower.

Fruit and Vegetable Peels as Efficient Renewable Adsorbents for Removal of Pollutants from Water: A Research Experience for General Chemistry Students

Sustainability is emerging as a prominent curricular initiative at the undergraduate level, and as a result, involving students in real-world problems in the classroom and laboratory is an important goal. The specific problem of a dwindling supply of clean and safe drinking water is also of utmost importance and relevance. This general chemistry laboratory curriculum provides first-year students with an opportunity to design and implement their own experiments that employ fruit and vegetable peels as adsorbents to remove pollutants from water. The project is nine laboratory periods long, with the first 2 weeks devoted to providing students with the necessary tools to perform original research. In the third week, students visit the Dickinson College farm and brainstorm possible hypotheses. Working in pairs, students perform original research in the fourth through sixth weeks and investigate adsorption capacity and percent removal. In the final 3 weeks, students perform calculations and engage in peer revie...

A green determination of an equilibrium constant: teaching new skills

Abstract The spectroscopic determination of an equilibrium constant is a classic experiment in the general chemistry laboratory curriculum. Here we describe a new version of this experiment, incorporating green chemistry practices into the general chemistry lab curriculum and directly teaching students about the principles of green chemistry. This lab studies the formation of the iron(III) salicylate complex ion, which is a more benign chemical system than the traditional iron(III) thiocyanate complex. A microtiter plate reader is used to reduce sample volumes, also giving students important experience using research-grade instrumentation. In addition, students gain more experience using adjustable manual micropipettors. Students responded positively to the lab, appreciating the green nature of the lab and the introduction of the plate reader, and student comments suggested that this lab successfully introduces green chemistry concepts to the general chemistry curriculum.

Characterizing Instructional Practices in the Laboratory: The Laboratory Observation Protocol for Undergraduate STEM

Chemistry laboratories play an essential role in the education of undergraduate Science, Technology, Engineering, and Mathematics (STEM) and non-STEM students. The extent of student learning in any educational environment depends largely on the effectiveness of the instructors. In chemistry laboratories at large universities, the instructors of record are typically graduate or undergraduate teaching assistants (TAs). Despite the importance of their role in the education of undergraduate students, TAs’ instructional practices have been largely understudied outside specific reform efforts. In this study, we developed a segmented observation protocol, the Laboratory Observation Protocol for Undergraduate STEM (LOPUS), in order to characterize TAs’ instructional styles in a General Chemistry laboratory curriculum. LOPUS captures both students’ and TAs’ behaviors every 2 min as well as initiators of verbal interactions and the nature of these verbal interactions (e.g., data analysis, explanation of concepts). ...

General Chemistry Students’ Goals for Chemistry Laboratory Coursework

Little research exists on college students’ learning goals in chemistry, let alone specifically pertaining to laboratory coursework. Because students’ learning goals are linked to achievement and dependent on context, research on students’ goals in the laboratory context may lead to better understanding about the efficacy of lab curricula. This study characterized undergraduate students’ learning goals for general chemistry laboratory coursework by recording video of students completing laboratory experiments and interviewing the students about their experiences. The data was analyzed utilizing the framework of learning domains as described by Human Constructivism. Students were found to be primarily guided by affective goals, such as the desire to feel good by completing the requirements and getting done early. This stood in conflict with any psychomotor or cognitive goals they held concurrently. The data provide suggestions for reform of the general chemistry laboratory curriculum.

Implementation of Gas Chromatography and Microscale Distillation into the General Chemistry Laboratory Curriculum as Vehicles for Examining Intermolecular Forces

As part of an NSF-funded Course Curriculum and Laboratory Improvement (CCLI) project that seeks, in part, to increase student exposure to scientific instrumentation, a gas chromatography experiment has been integrated into the second-semester general chemistry laboratory curriculum. The experiment uses affordable, commercially available equipment and materials. It also parallels the corresponding lecture topics, reinforcing the concept of intermolecular forces (and exposing the structural basis of these forces) through the drawing of Lewis structures, microscale distillation, and gas chromatography. Group presentations end the laboratory session, exposing all students to the entirety of analytical data obtained by their peers. Students respond favorably to the exercise, citing use of the gas chromatograph as interesting and the group presentations as highly beneficial to their understanding of the material.

Clock Reaction: Outreach Attraction

Chemistry students are often introduced to the concept of reaction rates through demonstrations or laboratory activities involving the well-known iodine clock reaction. For example, a laboratory experiment involving thiosulfate as an iodine scavenger is part of the first-year general chemistry laboratory curriculum at Dalhousie University. With the necessary materials, expertise, and laboratory space readily available, this undergraduate clock reaction experiment was modified to make it accessible to grade 9 students. The revised, qualitative experiment has been performed as an on-campus outreach initiative with eight grade 9 classes, reaching a total of 250 students, teachers, parents, and aides. The activity was facilitated by graduate student volunteers, who assisted the grade 9 students as they were exposed to a colorful adventure involving kinetics, chemical reactions, and catalysis. In general, adapting undergraduate experiments offers researchers and educators a positive and efficient way to introduce younger students to a university chemistry laboratory.

Testing the effectiveness of visual aids in chemical safety training

This study investigates the effectiveness of safety-related visual aids to enhance learning. It discusses the incorporation of safety-related visual aids into undergraduate general-chemistry laboratory curriculum. A comparison of post-exam responses shows that students of experimental group (n = 89), those who used visual aids during the trial period, achieved better than that of control group (n = 83) who do not use visual aids (t = 8.52 and p

Assessment of Antioxidant Capacities in Foods: A Research Experience for General Chemistry Students

With the booming interest in health food and nutrition, investigations of the antioxidant capacities of various foods have come to the forefront of food science. This general chemistry laboratory curriculum provides students with an opportunity to design and implement their own experiments relating to antioxidants in food. The curriculum is six laboratory periods long, with the first three laboratory periods providing students with the tools to investigate total antioxidant capacity, polyphenolic flavanoid content, and ascorbic acid concentration of samples. In the final three laboratory periods, students review food science literature, develop a hypothesis, design and perform their experiment, and present their findings in a scientific paper. This curriculum provides students with knowledge of UV–vis spectroscopy, high-performance liquid chromatography, food chemistry, and the practice and nature of science.

Interdisciplinary, Application-Oriented Tutorials: Design, Implementation, and Evaluation

At Washington University, fifteen Web-based tutorials were developed for our general chemistry laboratory curriculum. Each tutorial accompanies an experiment, wherein the key concepts of each tutorial complement the key concepts in the corresponding experiment. These tutorials are interdisciplinary applications that help make connections between the students' science courses and their everyday experience. In fall 2000 we performed an assessment to gauge the impact of the integration of these tutorials into the laboratory curriculum on students' attitudes about chemistry and their performance on a chemistry proficiency exam. The study used a pretest–posttest format with a control-group comparison. Washington University students had significantly more positive attitudes about chemistry than did the control students. Evidence is also presented that suggests that this curriculum or the measures used in evaluating student performance therein are beneficial to the performance of female students. These online tutorials are freely available for use by instructors at other institutions.

Reduction of experimental scale in high school and college general chemistry laboratories

The careful observation of chemical reactivity phenomena has been and should be an important part of the general chemistry laboratory curriculum. Reduction of experimental scale will help to ensure, in times of rampant chemophobia, that it remains so.