General Chemistry Laboratory Research Articles

Developing Student Process Skills in a General Chemistry Laboratory

Laboratory coursework is widely considered to be an integral part of chemistry undergraduate degree programs, although its impact on students’ chemistry knowledge is largely unsubstantiated. Labora...

Assessing Affective Differences between a Virtual General Chemistry Experiment and a Similar Hands-On Experiment

To date, few general chemistry laboratory studies have included affective measures despite calls for more research on aspects of this domain. This shortage of studies may be partially due to the scarcity of affective measures that have been designed for, or tested in, the college laboratory setting. To provide measures for use in this environment, several existing affective scales were adapted for this new context. Before data from the scales were utilized to study the environment, evidence was provided for the validity and reliability of the data generated from them. Once sufficient evidence was provided, it was possible to determine affective differences between students completing a Beer’s law experiment in the traditional hands-on laboratory (control group) and a similar experiment in a virtual environment (treatment group). To assess expected differences between environments, scales for anxiety, emotional satisfaction, intellectual accessibility, usefulness of lab, equipment usability, and open-endedness of lab were selected. To account for potential between-student differences, scales for feeling-related initial interest and value-related initial interest were selected. Overall, students who completed the virtual experiment scored significantly lower on the emotional satisfaction, intellectual accessibility, usefulness of lab, and equipment usability scales. However, it was noted that student responses in the virtual environment varied significantly by which teaching assistant (TA) instructed the section. To test for a possible instructor effect, data from the virtual sections were grouped by TA as “Virtual Group A” and “Virtual Group B”. Group A contained the TAs who had sections with lower averages on the emotional satisfaction scale as compared to group B. After controlling for instructor, differences between student responses in the “Hands-On” sections and “Virtual Group A” sections were no longer significant while significant differences remained between the responses in the “Hands-On” and “Virtual Group B” sections. This outcome indicated that the TA instructing the course may have been more influential on students’ affective outcomes than the environment in which the experiment was performed.

Graphing Activity for the First General Chemistry Lab Session to Introduce Data Processing

The first day of lab was traditionally a day to check into lab drawers, discuss lab safety, and perform a basic primer in graphing with Microsoft (MS) Excel, but it now includes an activity that involves reproducing a rather complex graph from the scientific literature. The activity is designed to give the students a brief introduction to the layout of a scientific article; its similarity to the scientific process; and basic statistics, including mean and standard deviation. The task of reproducing the graph from the literature requires students to demonstrate their ability to perform calculations using MS Excel, plot multiple series on one graph, display trendlines, use a secondary axis, and employ custom error bars. The mastery of these skills is apparent to the students and instructors by inspection of the completed graph and grading of the spreadsheet and postactivity questions using a rubric that is specific to the learning outcomes (96.3% class average). Furthermore, the graph to be duplicated is chosen from a paper coauthored by an undergraduate from our university, which creates a sense of relevance to the students. Using an article from our institution also provides the advantage of having access to the raw data, which are not always found in the literature. The incorporation of this activity into the first lab session of our introductory first-year chemistry course has resulted in the instructors of this and subsequent courses to rarely need to assist students in creating graphs, which are the routine conclusion to many lab sessions.

Incorporating chemical safety awareness as a general education requirement — Case study

An activity was added to the General Chemistry Laboratory to assess environmental awareness associated with the use of everyday consumer products. The activity promoted the reading and understanding of label information for different types of consumer products and helped students review information from a safety data sheet. The activity included the use of a mini-hazard analysis. As this is a case study of its initial implementation, the initial results have indicated that the students are better prepared for subsequent safety discussions of individual laboratories due to the timing of the activity at the beginning of the semester, and subsequent use of the skills developed. Student evaluations indicated that they increased their reading of labels and other information associated with the products they used.

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.

Analysis of copper alloys as an introduction to data analysis and interpretation for General Chemistry courses

The work herein presents a laboratory experience designed to foster clear connections between chemistry concepts, experimental measurements, and laboratory techniques. The experience consists of three different experiments to be completed in sequence over several laboratory sessions. First the density of the samples is determined, then the specific heat capacity is measured, and finally the cooling curves are determined for the analytes. The experimental work covers fundamental concepts in chemistry (i.e., density, calorimetry, and first-order kinetics), and guides students to develop an overarching comprehension of the chemical and physical properties of the analytes. The analytes are copper alloys with other metals (i.e., Sn, Zn, and Al) with variable chemical compositions. These alloys are robust (i.e., thermally stable, durable), and allow for the collection of reproducible data under the proposed experimental design, as shown in the work herein. The discussion of student-gathered data and results supports the feasibility of the laboratory experience for its implementation in General Chemistry laboratory programs.

Determining Iron(III) Concentration in a Green Chemistry Experiment Using Phyllanthus emblica (Indian Gooseberry) Extract and Spectrophotometry

A laboratory experiment utilizing locally available Indian Gooseberry (Phyllanthus emblica Linn.) extract as a bioreagent to determine iron(III) is described with the goal of providing students with hands-on experience in spectrophotometry and green chemistry. Spectrophotometry was used to measure the concentration of the complex formed between iron(III) and gallic acid, an active compound found in Indian Gooseberry extract. Excellent results from the quantitative analysis of iron(III) in water were achieved. In this case, the bioreagent was used to replace the conventional hazardous chemicals that are usually employed as chromogenic reagents. The use of Indian Gooseberry extract is simple, inexpensive, and environmentally friendly. This experiment is appropriate for use as a simple spectrophotometric protocol for undergraduate teaching in an analytical- or general-chemistry laboratory.

A Closed-Type Wireless Nanopore Electrode for Analyzing Single Nanoparticles.

Measuring the intrinsic features of single nanoparticles by nanoelectrochemistry holds deep fundamental importance and has potential impacts in nanoscience. However, electrochemically analyzing single nanoparticles is challenging, as the sensing nanointerface is uncontrollable. To address this challenge, we describe here the fabrication and characterization of a closed-type wireless nanopore electrode (WNE) that exhibits a highly controllable morphology and outstanding reproducibility. The facile fabrication of WNE enables the preparation of well-defined nanoelectrodes in a general chemistry laboratory without the use of a clean room and expensive equipment. One application of a 30 nm closed-type WNE in analysis of single gold nanoparticles in the mixture is also highlighted, which shows a high current resolution of 0.6 pA and high temporal resolution of 0.01 ms. Accompanied by their excellent morphology and small diameters, more potential applications of closed-type WNEs can be expanded from nanoparticle characterization to single molecule/ion detection and single-cell probing.

Bioplastics in the General Chemistry Laboratory: Building a Semester-Long Research Experience

We report here a second semester general chemistry laboratory project themed around chitosan-alginate bioplastics. With increasing awareness of plastic pollution in the environment and the awareness of the importance for materials which are either made from renewable resources or are biodegradable, this topic provides a relevant opportunity to engage students. The semester-long laboratory experience has students working in teams first to complete a series of core experiments which provide a foundational experience in preparing and testing chitosan-alginate bioplastics prior to developing and implementing a project in a direction of their own choosing. The benefit of these student directed research projects can include enhanced engagement and can allow development of skills such as experiment design, data collection and analysis, written and oral dissemination, and critical thinking. We describe here both the core module in bioplastics which has the potential to be incorporated as a self-contained module b...

Effective and Inexpensive HPLC Analogue for First-Year Students: Buret Chromatography of Food Dyes in Drinks

Chromatography is a ubiquitous technique in analytical chemistry, and high-performance liquid chromatography (HPLC) is the industry standard for quantitation of components in solution mixtures. However, demonstrating the principles of liquid chromatography to undergraduates via HPLC-based experiments often proves ineffective because of the fully automated nature of modern HPLC units. This paper details a novel laboratory exercise that is accessible to students in first-year chemistry and high school and helps to demonstrate and demystify the principles involved in HPLC. Using only common and inexpensive laboratory equipment found in most general-chemistry laboratories (burets and benchtop spectrophotometers), students are able to replicate results that are equivalent to those obtained on research-grade HPLC instruments, while gaining valuable insight into chromatography principles.

Helping Students to “Do Science”: Characterizing Scientific Practices in General Chemistry Laboratory Curricula

Over the past 20 years research on reform efforts aimed at the chemistry laboratory has focused on different aspects of students’ experiences including increasing content knowledge, improving stude...

Facilitating Argumentation in the Laboratory: The Challenges of Claim Change and Justification by Theory

Scientific argumentation is a key means by which students make sense of content and processes in inquiry-based instruction. In scientific argumentation students make a claim that they support with evidence and provide reasoning as to how the evidence supports the claim. Integrating the different aspects of scientific argumentation can be challenging for students especially if they need to make a claim change to accommodate new evidence. This study examines student argumentation within a two-semester general chemistry laboratory sequence at a minority-serving, comprehensive university in the Midwest, which employed the Argument-Driven Inquiry (ADI) instructional model for laboratory instruction. Video recordings of group argumentation from four investigations, two each semester, were coded using the Assessment of Scientific Argumentation in the Classroom (ASAC) observation protocol. On the basis of the data, students did not tend to change their claims or reasoning even when provided with contradictory evi...

3D‐printed Portable Platform for Mechanized Handling and Injection of Microvolumes Coupled to Electrochemical Detection

AbstractWe present a low‐cost mechanized system fabricated using fused deposition modelling 3D‐printing technology to manipulate microvolumes and perform injections on an electrochemical cell in wall‐jet configuration. As a proof‐of‐concept, the amperometric detection of paracetamol (model analyte) on a screen‐printed electrode using 0.5 μL aliquots resulted in highly reproducible responses (RSD <3 %). Moreover, handling of microliter aliquots of butylhydroxytoluene (phenolic antioxidant) and 2,2‐diphenyl‐2‐picrylhydrazyl (DPPH) to promote the radical‐scavenging reaction to determine antioxidant capacity by electrochemical detection of residual DPPH was demonstrated (time‐controlled reaction). A final application of the system was devoted to the analysis of cocaine and a common adulterant found in seized samples. The mechanized 3D‐printed analytical platform is capable to execute diverse sample preparation steps on board by handling microliter aliquots and subsequent electrochemical detection. 3D‐printing technology enabled the fabrication of a versatile and low‐cost (<U$200) mechanized system accessible to general chemistry labs.

Online pre-laboratory tools for first-year undergraduate chemistry course in Uruguay: student preferences and implications on student performance

As a fundamental part of their chemical education, first-year undergraduate students are substantially involved in laboratory activities. Despite the specific teaching staff choices on the main laboratory aims, students normally receive a vast amount of information during these activities. Apart from understanding theoretical content, fundamental skills such as manipulation, data collection and interpretation should be developed. In this context, learners could feel overwhelmed since they can only process a few pieces of information at a time. Indeed, our experience at theUniversidad de la República(Uruguayan public university) shows that many first-year students are in fact not able to cope with all the information they receive during laboratory activities. As a result, many of them only follow the experimental protocol automatically, without gaining significant knowledge or developing the necessary skills. In this work, we assessed the use of new online interactive pre-laboratory activities implemented for 252 first-year university students enrolled in a 12-module General Chemistry laboratory course. The student choice of interactiveversusmore traditional material was evaluated together with observed preferences regarding the different interactive tools offered. Besides, an online pre-laboratory discussion forum was also implemented and assessed. Both the interactive material and the discussion forum were chosen freely by the majority of students (61% and 79%, respectively). Interestingly, the choice was to some extent modulated by student previous performance. Interactive pre-laboratory material was more frequently chosen by low previous performance students, whereas pre-laboratory forum was preferentially used by high previous performance students. Finally, the influence of these new materials on student laboratory performance was statistically analyzed. Other personal and academic variables were also taken into account. Interactive material access was positively correlated with the final laboratory marks for medium previous performance learners. On the other hand, for lower previous performance students, the academic discussion between teachers and partners promoted by the online forum was positively correlated with their academic performance.

Effect of drawing on science students’ recognition of chemistry laboratory equipment and material

The purpose of this research is to examine the effect of drawing on recognition of chemistry laboratory equipment and material and uses of those. The research has been conducted with 80 students attending Science Teacher Department in their freshmen year at a university in Turkey. In this research was used quasi-experimental method with pretest-posttest control group. During the 10 weeks course of the research general chemistry laboratory classes were conducted with only the verification method with the control group whereas the experimental group used drawing alongside the verification method. The experimental group was asked for 10 weeks to draw the material they used in laboratory experiments and write down their uses. The research reached at the conclusion that the extra drawing method as applied to the experimental group is more effective in recognition of laboratory equipment and material frequently used in chemistry experiments in comparison to application of verification method alone as it was with the control group.

Pre-Service Science Teachers’ Development and Use of Multiple Levels of Representation and Written Arguments in General Chemistry Laboratory Courses

The purpose of this study was to examine pre-service science teachers’ (PSTs) development of multiple levels of representation and written arguments using an immersive approach to argument, the science writing heuristic, in general chemistry laboratory I and II courses. Fifty PSTs participated the study, 20 experiments were performed, and 976 samples were collected over two semesters. A case study design was used. The data were evaluated in three ways: the first was to examine the total number of representations used and connectedness of these representations, the second was to use analytical and holistic frameworks to evaluate PSTs’ written argument, and the third was to use a Wilcoxon Signed-Rank test to compare the scores gathered from the representations and argumentation. The results showed that PSTs’ holistic argument and multiple levels of representation increased over time, they showed parallel patterns, and the increasing quality of argument and use of representations were intertwined. The results also indicated that PSTs predominantly used the symbolic level of representation and used it as a mediator between the macroscopic, microscopic, and algebraic levels. The argument components of evidence and reflection appear to be critical areas in which the PSTs used more connected levels of representations, and PSTs were selective in using representations. The results of this study suggest that students should be provided with opportunities to use, generate, interpret, and reflect on these representational levels through the use of writing and negotiation activities as part of being involved in an argument-based laboratory environment.

Online based performance assessment for general chemistry laboratory

The purpose of this study is to describe the stages of making the performance assessment instrument and analyzing the results of the feasibility test of the online-based performance assessment instrument on the Basic Chemistry practicum. The method used is research and development. The results show that research phases include chemical material analysis, making performance assessment instruments, website creation, validation and limited trials. Validation is done to material and media expert validators, limited trials conducted to students and assistants of Basic Chemistry practicum. Validation of making of performance assessment instrument has value of rcount 0,95, while result of validation of making website of instrument of performance assessment has value of rcount 0,84. It shows that online-based performance assessment instrument on Basic Chemistry practicum interpretation is valid and has high feasibility of assessment of expert validator. The results show that the feasibility test based on a limited trial give good response with an average of 97.5% and 98.8%. The result of the percentage of the feasibility test indicates that the online-based performance assessment instrument on the Basic Chemistry practicum is eligible for use. Making this website is expected to facilitate lecturers in conducting the assessment of the performance of students at the time of practicum.

Electronic Laboratory Notebooks Allow for Modifications in a General, Organic, and Biochemistry Chemistry Laboratory To Increase Authenticity of the Student Experience

When used effectively, laboratory courses can be very important for enriching teaching and learning. However, a review of many colleges and universities across the nation reveals that around 50% of...

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.