Introductory Chemistry Laboratory Research Articles

Determination of chemical composition in Tri-Metal Alloys: a three variable linear equation system approach

To enhance the bridge between macroscopic and symbolic representations in chemistry, we crafted a laboratory module focusing on a three-equation system for chemical composition analysis. Students assess the composition of copper, tin, and aluminum alloys by measuring two properties: density and heat capacity. These non-destructive procedures fit within standard laboratory session durations. After gathering data, students tackle three linear equations linking element mass ratio to alloy composition, density, and heat capacity. By pooling data from various samples, the class achieves a comprehensive understanding. This method aligns with objectives for laboratory education, emphasizing scientific reasoning, practical skills, and subject mastery. Students’ results deviated by +/-10% from actual alloy compositions. The discussion of student-gathered data and results supports the feasibility of the laboratory experience for its implementation in introductory chemistry laboratories.

Critiquing lab technique videos prior to class: can it improve demonstrated technique?

During COVID-19 remote instruction, instructors were tasked with providing students with authentic laboratory experiences in an out-of-classroom environment. One solution developed for our introductory general chemistry laboratory involved students critiquing readily available technique videos to distinguish between correct and incorrect laboratory technique. After returning to in-person labs in Fall 2021, we incorporated this assessment into the pre-lab assignments in an effort to reduce the cognitive load of learning a new technique. Here we explore whether this critical-review exercise translates into improved technique as measured by precision and accuracy when using a 10 mL volumetric pipet. Additionally, we consider the impact of the pre-lab assignment given the involvement level of the TA, as some TAs are more willing to provide feedback on student technique during the lab period. We found that while students self-report the exercise as useful towards their learning, there are no significant changes in performance for most students. We did, however, find a reduction in the overall outliers and saw improvements when additional feedback (through a TA) was provided as well. These findings indicate that the exercise may be most useful for students who make large errors and who receive little individualized feedback.

Partnering with students to redesign an introductory chemistry laboratory course: An exploration of the process and implications

The most effective teaching and learning environments are those in which students are involved as active partners with faculty, and the greatest impact occurs when faculty go beyond asking students for feedback and instead involve them in design, production, and implementation. In this paper, we explore the process of student-faculty co-creation by presenting a specific case involving students as partners in the redesign of an introductory chemistry laboratory course to incorporate more group learning, support students’ skill development, and increase students’ sense of belonging in chemistry. This case study investigates how faculty can set up and structure a successful co-design partnership and attend to potential challenges as well as how educational developers and teaching centers can work in partnership with faculty and students to design or redesign courses.

Development of an Infographic Assignment for an Introductory Chemistry Laboratory Curriculum

In recent years, pedagogical advancements have allowed the adoption of more engaging forms of course assignments to help students better understand and communicate chemistry. In this context, informational graphics, known as infographics, emerge as an effective teaching aid in educational settings and in disseminating scientific content to the public. This article describes the design of an infographic assignment and its implementation in a first-year chemistry laboratory course at the University of British Columbia’s Okanagan campus. The overarching goal of this assignment was to incorporate the thematic framework of the United Nations Sustainable Development Goals into the laboratory curriculum while encouraging systems thinking and promoting science communication initiatives. The students’ attitudes toward this assignment via submitted self-reflection survey results are also discussed. Our findings reveal an overall positive student experience suggesting the infographic assignments’ ability to foster student engagement and critical thinking skills.

Finding the variables that react: Relationships between ability beliefs and student achievement in an inquiry‐based introductory chemistry laboratory course

AbstractThis quantitative, exploratory study examined whether a Project‐Based Guided Inquiry (PBGI) chemistry laboratory course supported more incremental ability beliefs among students, examined achievement outcomes for students grouped based on changes in student‐reported chemistry ability beliefs from pre‐ to post‐course, and provided explanations for differences in achievement and chemistry ability beliefs. Data sources included pre/post surveys of 367 undergraduate students' and 18 teaching assistants' (TAs) content knowledge, ability beliefs, sociodemographics (e.g., gender, race), and prior chemistry experience. The hierarchical linear regression (HLR) model accounted for 27.4% of the variance in post‐content scores, with male students and students with more prior chemistry experience scoring significantly higher than their counterparts. Student ability beliefs was not a significant predictor of content knowledge at the end of the course. Women had a significant decrease in their ability beliefs while male students did not. Furthermore, there were significant differences in achievement depending upon whether and how students' chemistry ability beliefs changed during the course. HLR indicated that student race and TA research experience significantly predicted students' ability beliefs and accounted for 32.7% of variance in this model. Finally, students had more positive perceptions of their TA when their TA held more incremental ability beliefs. These results also indicate that redesigning undergraduate chemistry labs to a PBGI approach does not necessarily level the academic playing field for students who identified as Black, Hispanic, or Multi‐racial, women, or students with less chemistry experience. Providing additional scaffolding for students and developing professional learning experiences to explicitly support TAs incremental ability beliefs may be beneficial in reform‐based laboratory contexts. Further research is needed to understand who benefits from reform‐based instruction and for what reasons.

Incorporating Interlab Collaborations into the Organic Chemistry Teaching Laboratories

Collaborative experiences have been widely integrated into the classroom and laboratory, with goals to build time management, communication, and team-working skills. Most reported laboratory collaborations occur between students within the same lab section, which could limit the potential benefits of these experiences. Presented herein is an organic chemistry laboratory model in which students collaborate across lab sections (i.e., interlab collaborations) to complete discovery-based, medicinal-chemistry-focused experiments. These experiences provide opportunities for students to reflect on and improve upon their team-working skills. Over the past three years, interlab collaborations have been offered at Muhlenberg College to 105 students in two types of organic chemistry courses. Assessment data, including notebook evaluation scores, peer- and self-evaluations, lab report scores, and student reflections, suggest that these experiences could help build time management, communication, organizational, and data-recording skills. These laboratories could give students a realistic view of collaborative work and allow for the intentional development and assessment of team-working skills in any introductory or upper-level chemistry laboratory. Furthermore, this model provides a framework for reducing lab section sizes by half, a change which has been needed during COVID-19, while still completing the planned lab curriculum.

Introductory Chemistry Laboratory: Quantum Mechanics and Color

Laboratory experiments provide students a tangible means of understanding dry, abstract concepts. A simple and engaging introductory wet chemistry laboratory has been developed relating quantum mechanics to color, which has been implemented for a class of about 600 students per academic year for over three years at Brown University. Color is an important aspect of daily life, used to communicate meaning and emotion. Nanoparticles, organic dyes, and metal complexes produce color in medieval stained glass, textiles, and gemstones, respectively. Though they can produce visually similar colors, the microscopic mechanisms of color production are different. The origins of color are used to facilitate the discussion of quantum mechanics and bonding concepts. The relation of these color producing model systems to chemical concepts also serves as motivation for an introduction of advanced concepts, such as nanochemistry, to first-year undergraduate students. Students synthesize silver nanoparticles of different shapes and sizes and use UV–vis spectrophotometers to characterize them along with additional unknown colorful solutions made from either metal complexes or organic dyes. Relating quantum mechanics and bonding to color in daily life excited students, promoting learning. This laboratory can be adapted for K–12 students.

Precision and Accuracy: Knowledge Transformation through Conceptual Learning and Inquiry-Based Practices in Introductory and Advanced Chemistry Laboratories

Whereas extensive studies have examined the effectiveness of inquiry-based learning in chemistry education, few have tracked undergraduate performance throughout the college chemistry curricula. In this study, we describe an instructional model of conceptual learning and inquiry-based practices (CLIP) and assess students’ transformation of knowledge about precision and accuracy in the laboratory components of Introductory Chemistry, Analytical Chemistry, Instrumental Analysis, and Physical Chemistry. Student performance in written laboratory reports reveals that repetition of concepts and specific feedback from instructors are essential in constructing knowledge about precision and accuracy. We observed a distinct gap between students’ perception of their understanding and their ability to determine precision and accuracy in data sets. This gap decreases as students move from introductory to advanced chemistry laboratories, but loss of student participants throughout the study increases the uncertainty in the significance. In contrast to traditional teaching, enhanced learning was observed in Introductory Chemistry I Laboratories thought CLIP, with the support of concept/skill training, specific feedback, and student-centered activities. This study benefits members of the community who are engaged in supporting students’ mastery of theory with practice.

Ultrasonic-Assisted Synthesis, Characterization, and Application of a Metal–Organic Framework: A Green General Chemistry Laboratory Project

An instructional research-like multiweek laboratory project for a second-semester introductory general chemistry laboratory course has been developed. The ultrasonic-assisted synthesis method using low cost commercial ultrasonic cleaners has the convenience of running multiple students’ reactions simultaneously. Taking advantage of short reaction time, the green metal–organic framework project has been developed to facilitate experimental synthesis, characterization, and application of a porous material and debriefing of results during a normal laboratory period (about 3 h/class). This project provides the opportunity for instructors to introduce students to the Twelve Principles of Green Chemistry, the environmental impact of chemistry, modern solid-state analytical techniques, and a research-like experience of materials science.

Relationship between teaching assistants’ perceptions of student learning challenges and their use of external representations when teaching acid–base titrations in introductory chemistry laboratory courses

Practicing chemists use models, diagrams, symbols, and figures to represent phenomena which cannot be detected by the human senses. Although research suggests that these external representations (ERs) can also be used to address the challenges that students have in learning chemistry, it is not clear how instructors' use of ERs aligns with their perceptions of student learning difficulties. In other words, do instructors use ERs to address what they perceive as students' major challenges in learning chemistry, or are they using ERs for other reasons? The answer to this question could have implications for the professional development of chemistry instructors, including both classroom instructors and laboratory facilitators. As a pilot study to guide the development of a larger project focused on the use and interpretation of ERs, we interviewed eleven general chemistry teaching assistants at a major university in the U.S. Southwest about their use of ERs when facilitating acid–base titration laboratory activities. Our data suggest that there is a lack of alignment between teaching assistants’ primary reported use of ERs and the primary challenge that they perceive their students have when learning about acid–base titrations. We discuss potential reasons for this misalignment, as well as implications for teaching assistant training related to the use of ERs in the laboratory learning environment.

Structured learning environments are required to promote equitable participation

It is critical that we understand and address features of learning environments that encumber students historically underrepresented in STEM fields. Here we consider social elements of group work that can either support or impede learning. We tracked gender-bias in student–teaching assistant (TA) interactions in 184 small groups across 27 introductory chemistry laboratories in fall 2017. We demonstrate that in some environments male students interacted with TAs disproportionately more than female students. To promote verbal participation of women in introductory chemistry courses, we advocate for improved TA training programs that teach a host of equitable teaching strategies to enhance the climate of the classrooms and consequently, improve learning. Fostering a structured, inclusive classroom environment is the first step towards achieving equity more broadly across STEM.

The Effect of Multiple Representations of Physical and Chemical Changes on the Development of Primary Pre-service Teachers Cognitive Structures

The purpose of this study was to describe the effect of multiple knowledge representations of physical and chemical changes on the development of primary pre-service teachers’ cognitive structures. The study took place in an introductory general chemistry laboratory course in a four-year teacher education program. Multiple knowledge representations in chemistry refer to the macroscopic (visible), sub-microscopic (invisible), and symbolic (formulas and equations). The study adopted one group pretest-posttest design supported by qualitative data. Forty primary pre-service teachers participated in this study. The results revealed that enabling the primary pre-service teachers to learn multiple representations of physical and chemical changes was effective in developing both groups of pre-service teachers’ cognitive structures, low and high-level understanding of particulate nature of matter, the latter benefitting the most. This finding was instructive because it emphasizes the difficulty that some primary pre-service teachers had on the particulate and symbolic representations of physical and chemical changes. The improvement in primary pre-service teachers’ cognitive structures of physical and chemical change by the use of multiple representations.

Polar Plunge: Semester-Long Snow Chemistry Research in the General Chemistry Laboratory

An introductory general chemistry laboratory course was developed to provide an authentic research experience in environmental chemistry. First- and second-year students learned general chemistry concepts and laboratory skills in the context of snow chemistry while participating in the course-based undergraduate research experience. Students were guided through all steps of the research process, including research question development, data collection and processing, interpretation of results in the context of scientific literature, and both written and oral presentations. A key component of the course was an individual laboratory experiment in which snow samples from the Arctic were analyzed for pH and ion content. Assessment of the course via pre- and postcourse surveys indicated that students, the majority of whom were women, experienced greater gains in confidence of research skills and general attitudes toward chemistry as compared to the traditional general chemistry laboratory course. This course r...

Peer learning as a tool to strengthen math skills in introductory chemistry laboratories

Math skills vary greatly among students enrolled in introductory chemistry courses. Students with weak math skills (algebra and below) tend to perform poorly in introductory chemistry courses, which is correlated with increased attrition rates. Previous research has shown that retention of main ideas in a peer learning environment is greater when partners have dissimilar abilities. Therefore, in an effort to improve student learning outcomes, we implemented peer learning interventions in our introductory chemistry laboratories to determine if math skills were enhanced when partners differed in math ability. Student performance and attitudes were analyzed in laboratory sections consisting of instructor-assigned partners who differed in math ability, compared to sections where students self-selected a partner. Students who were assigned math partners of different ability showed an 8% improvement in chemistry math concepts compared to no improvement among those who self-selected a partner, as assessed using pre- and post-math tests. Mathematical learning gains were particularly large (16%) for those students in the 50th percentile of math performance. Students also reported a significantly more positive attitude change about working with others compared to students who self-selected a partner. In addition, assigned students demonstrated a more positive shift in self-concepts such as chemistry knowledge and laboratory skills. This study illustrates that peer learning can serve as a useful and easy-to-implement tool to strengthen math skills and improve student attitudes in introductory chemistry laboratories.

Synthesis of trans-4,5-Bis-dibenzylaminocyclopent-2-enone from Furfural Catalyzed by ErCl3·6H2O

An experiment exploring the chemistry of the carbonyl group for the one-step synthesis of trans-4,5-dibenzylaminocyclopent-2-enone is described. The reaction of furfural and dibenzylamine in the environmentally friendly solvent ethanol and catalyzed by the Lewis acid ErCl3·6H2O afforded the product in high yield (79–97%) with high purity by simple filtration. This experiment can be performed during a 3 h class, and requires only basic glassware without an anhydrous or inert atmosphere. It is suitable for use in introductory organic chemistry laboratories, where the purity of the product can be determined, using simple techniques such as TLC analysis and melting point measurement, as well as for more advanced classes allowing the consolidation of important reactivity features of the carbonyl group and the interpretation of the 1H NMR spectrum.

Dialysis, Albumin Binding, and Competitive Binding: A Laboratory Lesson Relating Three Chemical Concepts to Healthcare

Introductory Chemistry laboratories must go beyond “cookbook” methods to illustrate how chemistry concepts apply to complex, real-world problems. In our case, we are preparing students to use their chemistry knowledge in the healthcare profession. The experiment described here explicitly models three important chemical concepts: dialysis of small molecules (dye), reversible binding (dye binding to albumin), and competitive binding (dye and a competitor binding to albumin). Moreover, each concept is intimately related to a physiological phenomenon: dialysis is used to treat renal failure, drugs travel in the blood bound to albumin, and competitive albumin binding is a common drug–drug interaction. In the context of this simple series of experiments, students create models, use evidence to validate their models, and finally use their understanding to describe physiological phenomena. This laboratory experiment was implemented in a 100-level course for predominantly prenursing majors. Student pre- and postla...

Preparing and Testing a Magnetic Antimicrobial Silver Nanocomposite for Water Disinfection To Gain Experience at the Nanochemistry–Microbiology Interface

We describe a 2 h introductory laboratory procedure that prepares a novel magnetic antimicrobial activated carbon nanocomposite in which nanoscale sized magnetite and silver particles are incorporated (MACAg). The MACAg nanocomposite has achieved the synergistic properties derived from its components and demonstrated its applicability as an effective and recoverable antimicrobial agent for water disinfection. The principle is successfully illustrated by a significant reduction in the number of microbes in an Escherichia coli (E. coli) solution of 2 × 106 colony forming units following its treatment with MACAg for 10 min. The exercise allows the college students to (1) be introduced to an exciting class of advanced materials, known as nanocomposites, at an early stage, (2) gain working experiences at nanochemistry–microbiology interface, and (3) see the use and experience the fun of chemistry. The experiment uses readily available materials, can be run in a general or introductory chemistry laboratory envi...

Gold(III)-Catalyzed Hydration of Phenylacetylene

A guided inquiry-based experiment exploring the regioselectivity of the hydration of phenylacetylene is described. The experiment uses an acidic gold(III) catalyst in a benign methanol/water solvent system to introduce students to alkyne chemistry and key principles of green chemistry. The experiment can be easily completed in approximately 2 h, and is suitable for use in introductory organic chemistry laboratories. The experiment is versatile and amenable to many lab settings, as it requires no specialized glassware, and the crude product can be analyzed via gas chromatography, infrared spectroscopy, or nuclear magnetic resonance spectroscopy.

Determination of log Kow Values for Four Drugs

Though many undergraduates are interested in medicine, relatively few experiments related to drug design and development are included in introductory chemistry laboratory courses. In this experiment, aqueous solutions of four different drugs (acetaminophen, caffeine, phenacetin, and sulfanilamide) are extracted using 1-octanol, a mimic of the amphiphilic lipids that constitute cell membranes. UV analysis of the aqueous solutions before and after extraction allows determination of each compound’s log Kow value (partition coefficient), a property that influences a drug’s bioavailability. The concepts of equilibrium and hydrophobicity–hydrophilicity are emphasized, and students gain experience with micropipets in making dilutions. The lab has been implemented in a second-year undergraduate analytical chemistry course but may be suitable for organic, general, or medicinal chemistry depending on an institution’s particular curriculum.

A Process for Developing Introductory Science Laboratory Learning Goals To Enhance Student Learning and Instructional Alignment

Learning goal (LG) identification can greatly inform curriculum, teaching, and evaluation practices. The complex laboratory course setting, however, presents unique obstacles in developing appropriate LGs. For example, in addition to the large quantity and variety of content supported in the general chemistry laboratory program, the interests of faculty members from various chemistry subdisciplines and the service goals of such a course should be addressed. To optimize the instructional impact of limited laboratory contact time, achieve learning gains in basic and transferable (i.e., valuable in other sciences) laboratory learning content, and establish departmental consensus, a model was created for LG and assessment development that was inspired by interdisciplinary science laboratory LGs implemented at Rice University. These newly developed processes and materials were used to enhance the introductory chemistry laboratory curriculum at the University of British Columbia, involving a large (>1700 studen...