General Chemistry Laboratory Research Articles

First year chemistry laboratory courses for distance learners: Development and transfer credit acceptance

<p><span style="font-family: 'Times New Roman','serif'; font-size: 12pt; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: EN-US; mso-bidi-language: AR-SA;">In delivering chemistry courses by distance, a key challenge is to offer the learner an authentic and meaningful laboratory experience that still provides the rigour required to continue on in science. To satisfy this need, two distance general chemistry laboratory courses appropriate for Bachelor of Science (B.Sc.) students, including chemistry majors, have been recently developed at Thompson Rivers University. A constructive alignment process was employed which clearly mapped learning outcomes and activities to appropriate assessment tools. These blended laboratory courses feature custom, home experimental kits and combine elements of online and hands-on learning. The courses were designed for flexible continuous enrollment and provide online resources including tutor support, instructional videos, lab report submission, and student evaluation. The assessment of students includes laboratory reports, safety quizzes, reflective journaling, digital photo documentation, and invigilated written and online practical exams. Emphasizing the quality and rigour in these distance laboratory learning experiences allowed both courses to be accepted for B.Sc. transfer credit by other institutions, an important criterion for students. This paper will outline the design and development process of these new blended laboratory courses, their course structures and assessments, and initial student results.</span></p>

An examination of injuries and respiratory irritation symptoms among a sample of undergraduate chemistry students from a Public Northeastern University

Injuries have become an important indicator of safety and risks to health in the laboratory, but few studies have examined injuries among undergraduate chemistry students. Respiratory and mucous membrane irritation due to exposures were also important potential outcomes of present concern, because they were potentially related to factors such as physician-diagnosed asthma and smoking. The present study, with a cross-sectional design, implemented an anonymous online survey among a sample of students enrolled in general chemistry and first semester organic chemistry laboratory courses from a single northeastern university. Survey questions were assimilated from existing validated national surveys or developed (and approved by Institutional Review Boards) to obtain demographic information, acute injury status, respiratory irritation and mucous membrane irritation symptoms due to exposures in academic chemistry laboratories, physician-diagnosed asthma, primary active smoking, and secondary passive smoking. A Likert-scale was created to assess behavioral risk factors (BRF). A prepared recruitment email was sent to 1,704 undergraduate students enrolled in either general chemistry laboratory or organic chemistry laboratory in the winter–spring semester, 2012; 319 participants completed the online survey during the 27-day data collection period (response rate 18.7%). Two hundred and sixty-five valid records were analyzed. Prevalence of current semester injury (11%) and also current semester respiratory irritation (22%) in the winter–spring, 2012 semester were elevated. Analysis of variance models suggested gender, course of enrollment, birth year, and class standing were significantly related to BRF scores. Current semester injury and also current semester respiratory irritation during laboratory courses were not significantly related to BRF scores. Current semester respiratory irritation during laboratory courses was not significantly related to asthma after controlling for primary active and secondary passive smoking. Further applied research into undergraduate sciences laboratory safety and health evaluations are warranted.

Weak Acid Ionization Constants and the Determination of Weak Acid–Weak Base Reaction Equilibrium Constants in the General Chemistry Laboratory

A laboratory to determine the equilibrium constants of weak acid-weak base reactions is described. The equilibrium constants of component reactions when multiplied together equal the numerical value of the equilibrium constant of the summative reaction. The component reactions are weak acid ionization reactions, weak base hydrolysis reactions, and the auto-ionization of water reaction. The summative equations are weak acid-weak base reactions. The acid ionization constants (Ka) of HC2H3O2, H3PO4, H2PO4-, HPO42-, and NH4+ are determined from measurements of the pH in buffer solutions with known weak acid and known weak base concentrations, and base hydrolysis constants (Kb) are determined using Ka × Kb = Kw.

How To Recognize Success and Failure: Practical Assessment of an Evolving, First-Semester Laboratory Program Using Simple, Outcome-Based Tools

This paper presents the use of simple, outcome-based assessment tools to design and evaluate the first semester of a new introductory laboratory program created to teach green analytical chemistry using environmental samples. This general chemistry laboratory program, like many introductory courses, has a wide array of stakeholders within and beyond the major. Among the stakeholders, there was low-level yet widespread apprehension that changes in the introductory level content would weaken student preparation. Because of this unease, it was important to prove to faculty and students alike that the new laboratory program could effectively help students reach the new laboratory learning goals without sacrificing technical content. A set of simple assessment tools, student precision and accuracy data from experiments during the semester, and a laboratory practical and a student survey from the end of the semester were used as both formative and summative program assessments. This article establishes the power of these simple, course-embedded tools to yield insights into program strengths and weaknesses and, ultimately, to demonstrate to all faculty and students the effectiveness of this first-semester program.

Incorporating Professional Service as a Component of General Chemistry Laboratory by Demonstrating Chemistry to Elementary Students

Formalized participation in professional service is not often part of the college experience, especially for first-year students in chemistry courses. When service opportunities are offered, they are most often through elective credit, upper-level courses, extracurricular clubs, and the rare service-learning courses. We have successfully incorporated a large science service-learning opportunity into the general chemistry laboratory that provides multidisciplinary educational experiences for children and the community. The experience for the college students involves several weeks of preparation for a two-week laboratory module and participation in the public event on the university campus. College students involved in the second year of the event were surveyed to determine the impact of formalized participation in professional service on their attitude toward science and participation in future professional service events. Highly positive responses on the surveys and public interest in the event suggest c...

Characteristics of Indoor Aerosols in College Laboratories

This study was conducted in National Pingtung University of Science and Technology (NPUST), in Taiwan. The main objective was to provide quantitative information on concentrations of the indoor and outdoor PMs, as well as watersoluble ions, at seven selected locations and the spatial variations in four different types of typical laboratories. They include Type I: General Chemistry Laboratories (GCL); Type II: WCLTP during a semester and a summer vacation in college; Type III: Environmental Research Laboratories; and Type IV: Soil Research Laboratories and Field in NPUST. In addition, this paper also investigates the characteristics of indoor aerosols in college laboratories. Indoor and outdoor particulate matters with aerodynamic diameters of less than 2.5 μm (PM2.5) and 10 μm (PM10) were sampled from June to September in 2002. The acid and base gases in outdoor samples and the amount of eight particle-bound water-soluble ions (NO3 – , SO4 2– , Cl – , NH4 + , Na + , K + , Ca 2+ , and Mg 2+ ) were also determined. The results for laboratories Types I and II revealed that the mean PM2.5 concentrations indoors in GCL (during a semester) and WCLTP (during a summer vacation) exceeded the air quality guidelines of the World Health Organization (WHO) of 20 μg/m 3 for PM2.5. The results also showed that the indoor concentrations of PM2.5 and PM10 in GCL increased by 4.9 and 1.7 times, respectively, during a semester as compared to the indoor measured data during a summer vacation. Students’ laboratory activities in colleges thus deserve more attention, because these cause significant increases in the PM emissions.

¿Mejoran las simulaciones en los laboratorios de química el aprendizaje en todo tipo de alumnos? Percepciones de alumnos universitarios de primer curso de Química General.

The main purpose of this work is to analyze the perception of students enrolled in the General Chemistry Laboratory course at Suffolk University Madrid Campus on the improvement of their learning process through the inclusion of simulations in this lab course. This improvement will also be measured in a more objective way by means of the grades in the final exam. This report shows that a more positive perception is achieved in students with more visual skills, and that a more objective improvement is particularly observed in the grades of non science major students.

ConfChem Conference on Case-Based Studies in Chemical Education: Use of Case Study for the Introductory Chemistry Laboratory Environment

The teaching laboratory setting is conducive to active learning because of its practical nature and longer duration. Case study teaching in science has shown strength in its ability to integrate relevance, student involvement, basic scientific concepts, and science skills. Here we communicate the main points of our experience with developing and implementing a case study for general chemistry laboratory that necessitated experimentation within the framework of the case. First-time students and repeating students found the case study to be favorable, with 67.3% of repeating students indicating a preference for the case study versus the expository format of the same experiment. A principal goal was to determine the feasibility of using a case study teaching in the laboratory setting. Consequently, writing and conducting of the case study was an outcome in itself. Assessment indicates students find the case study relevant and like the incorporation of student choice for analysis of sample. The case study is flexible and potentially applicable to existing qualitative analysis experiments. For each cohort of students within our program, the case is modified for a unique experience.

Students’ Written Arguments in General Chemistry Laboratory Investigations

This study aimed to examine the written arguments developed by college freshman students using the Science Writing Heuristic approach in inquiry-based general chemistry laboratory classrooms and its relationships with students’ achievement in chemistry courses. Fourteen freshman students participated in the first year of the study while 19 freshman students participated in the second year of the study. Two frameworks, an analytical and a holistic argument framework, were developed to evaluate the written argument generated by students. The analytical framework scored each argument component separately and allocated a Total Argument score while the holistic framework evaluated the arguments holistically. Three hundred and sixty-eight samples from 33 students were evaluated. Stepwise regression analyses revealed that the evidence and the claims–evidence relationship components were identified as the most important predictors of the Total Argument and the Holistic Argument scores. Students’ argument scores were positively correlated with their achievement, as measured by the final grade received for the general chemistry laboratory and the general chemistry lecture course.

Mouse In A Can Revisited, Deep-Sea Carnivorous Harp

The Newscripts gang loves hearing readers’ reactions to our stories. For instance, Barbara Lewis, a chemistry lab instructor at Clemson University, wrote to tell us about how a Jan. 23 story inspired her to dissolve mice in soda. The story ( C&EN, Jan. 23, page 48) described a gag-inducing lawsuit filed by an Illinois man against PepsiCo. He claimed he found an intact, dead mouse in his can of Mountain Dew. A veterinarian hired by the soda company disputed the claim, saying any critter spending that much time in the acidic drink would have dissolved into a “jellylike substance.” Lewis decided to test the doctor’s claim as a demonstration for the 1,800 or so students in her spring general chemistry lab. A dentist quoted in the Newscripts story suggested that, compared with Pepsi, Mountain Dew might better dissolve bone and teeth. So Lewis filled one glass jar with Pepsi and ...

Effect of the Level of Inquiry on Student Interactions in Chemistry Laboratories

The central goal of our exploratory study was to investigate differences in college chemistry students' interactions during lab experiments with different levels of inquiry. This analysis was approached from three major analytic dimensions: (i) functional analysis; (ii) cognitive processing; and (iii) social processing. According to our results, which were based on the qualitative analysis of direct observations of different groups of students working in general chemistry laboratories, experiments that involved higher levels of inquiry were associated with an increase in the frequency of episodes in which students engaged in proposing ideas versus asking and answering each others' questions. Higher levels of inquiry also favored episodes in which experimental work was approached in a more exploratory (versus procedural) manner. Increased levels of inquiry were also associated with more frequent episodes of domination in which a few students in a group directed the actions of others. In general, our results elicit trends and highlight issues that can help instructors identify strategies to better support and scaffold productive engagement in the laboratory.

Using the Writing Template provided by the Science Writing Heuristic(SWH) approach for Quality Arguments

This study examined changes in the quality of written arguments produced by freshman students in general chemistry laboratory classes using the SWH approach over a semester; difference in the quality of written argument between the original writing template (year I) and the extended writing template (year II); and any difference between Total Argument and Holistic Argument scores. 140 writing samples from 14 students on the year I and 228 samples from 19 students on the year II were collected. Results indicated that despite fluctuations, the students were producing stronger argument by the end of semester compared to the beginning of the semester. Original SWH template group received significantly higher argument scores than extended SWH template group. For the most of year I laboratory investigations, there was no significant difference in the quality of argument between Total Argument and Holistic Argument scores. An implication of this study would be to provide opportunities for students to practice constructing arguments using the original SWH writing template including questions, claims, evidence, and reflection.

Playing with Light: Adventures in Optics and Spectroscopy for Honors and Majors General Chemistry

A lab was developed for use in an undergraduate honors and majors general chemistry laboratory to introduce students to optics, spectroscopy, and the underlying principles of quantum mechanics. This lab includes four mini-experiments exploring total internal reflection, the tunneling of light, spectra of sparklers and colored candles, and emission spectra of gases. These mini-experiments were of a mixture of styles, from open-ended inquiry, to more traditional cookbook experiments, and were chosen to echo current graduate research. In the accompanying lecture, students were given an overview of quantum mechanics and a primer on what type of information can be gleaned from a spectrum.

Discovering 13C NMR, 1H NMR, and IR Spectroscopy in the General Chemistry Laboratory through a Sequence of Guided-Inquiry Exercises

This sequence of three guided-inquiry labs is designed for a second-semester general chemistry course and challenges students to discover basic theoretical principles associated with 13C NMR, 1H NMR, and IR spectroscopy. Students learn to identify and explain basic concepts of magnetic resonance and vibrational spectroscopy; collect and interpret sets of 13C NMR, 1H NMR, and IR spectra; and correctly identify functional groups and chemical structures for a variety of simple organic compounds. Student survey data, along with in-lab observations of student interactions, lead to the conclusion that these lab experiences enhance student interest, increase communication between students, and improve their ability to explain and correct their own misconceptions.

An Investigative, Cooperative Learning Approach for General Chemistry Laboratories

The integration of research and education is an essential component of our university’s teaching philosophy. Recently, we made a curricular revision to facilitate such an approach in the General Chemistry Laboratory, to teach students that investigative approaches are at the core of sciences. The curriculum revision included new interdisciplinary experiments and a research project. Investigative, peer review, and cooperative learning strategies were introduced to enhance student learning and engagement. An environment in which students can analyze results within a laboratory session and reach comprehensive and quantitative conclusions was encouraged.

Argument-Driven Inquiry as a Way to Help Undergraduate Students Write to Learn by Learning to Write in Chemistry

This exploratory study examined how undergraduate students’ ability to write in science changed over time as they completed a series of laboratory activities designed using a new instructional model called argument-driven inquiry. The study was conducted in a single section of an undergraduate general chemistry lab course offered at a large two-year community college located in the southeast USA. The intervention took place over a 15-week semester and consisted of six laboratory activities. During each laboratory activity, the undergraduates wrote investigation reports, participated in a double-blind group peer review of the reports, and revised their reports based on the reviews. The reports written during each laboratory activity were used to examine changes in the students’ writing skills over time and to identify aspects of scientific writing that were the most difficult for the undergraduates in this context. The reviews produced by the students during each report were used to evaluate how well undergraduates engage in the peer-review process. The results of a quantitative and qualitative analysis of the reports and reviews indicate that the participants made significant improvements in their ability to write in science and were able to evaluate the quality of their peers’ writing with a relatively high degree of accuracy, but they also struggled with several aspects of scientific writing. The conclusions and implications of the study include recommendations for helping undergraduate students learn to write by writing to learn in science and new directions for future research.

Effectiveness of Podcasts Delivered on Mobile Devices as a Support for Student Learning During General Chemistry Laboratories

Chemistry instructors in teaching laboratories provide expert modeling of techniques and cognitive processes and provide assistance to enrolled students that may be described as scaffolding interaction. Such student support is particularly essential in laboratories taught with an inquiry-based curriculum. In a teaching laboratory with a high instructor-to-student ratio, mobile devices can provide a platform for expert modeling and scaffolding during the laboratory sessions. This research study provides data collected on the effectiveness of podcasts delivered as needed in a first-semester general chemistry laboratory setting. Podcasts with audio and visual tracks covering essential laboratory techniques and central concepts that aid in experimental design or data processing were prepared and made available for students to access on an as-needed basis on iPhones® or iPod touches®. Research focused in three areas: the extent of podcast usage, the numbers and types of interactions between instructors and student laboratory teams, and student performance on graded assignments. Data analysis indicates that on average the podcast treatment laboratory teams accessed a podcast 2.86 times during the laboratory period during each week that podcasts were available. Comparison of interaction data for the lecture treatment laboratory teams and podcast treatment laboratory teams reveals that scaffolding interactions with instructors were statistically significantly fewer for teams that had podcast access rather than a pre-laboratory lecture. The implication of the results is that student laboratory teams were able to gather laboratory information more effectively when it was presented in an on-demand podcast format than in a pre-laboratory lecture format. Finally, statistical analysis of data on student performance on graded assignments indicates no significant differences between outcome measures for the treatment groups when compared as cohorts. The only statistically significant difference is between students who demonstrated a high level of class participation in the concurrent general chemistry lecture course; for this sub-group the students in the podcast treatment group earned a course average that was statistically significantly higher than those in the lecture treatment group.

Comparing Mass and Volumetric Titrations in the General Chemistry Laboratory

Students in the general chemistry laboratory are commonly exposed to volumetric titrations as part of their laboratory curriculum. However, the use of mass burets instead of volumetric burets can save time, expense, and reduce errors. In this laboratory exercise, students are asked to standardize a solution of NaOH(aq) using potassium hydrogen phthalate and determine the acetic acid concentration in vinegar using both techniques. Students are then asked to compare the two approaches. When given a choice in a subsequent laboratory exercise, approximately 75% of the students choose to use the mass approach.

Identification of Unknown Chloride Salts Using a Combination of Qualitative Analysis and Titration with Silver Nitrate: A General Chemistry Laboratory

General chemistry students often have difficulty writing balanced equations and performing stoichiometry calculations for precipitation reactions, in part because of difficulty understanding the symbolic notation used to represent chemical reactions. We have developed a problem-based experiment to improve student learning of these concepts, and student surveys indicate this goal was achieved. Furthermore, this experiment requires students to integrate results from several different experiments and emphasizes critical-thinking and problem-solving skills. Students identify unknown chloride salts by (1) using a precipitation reaction to determine if the cation is a group 1 or group 2 metal, (2) performing a titration with silver nitrate to determine the formula mass of the salt, and (3) confirming the identity of the salt using a flame test. Students enjoyed the lab, and over 75% of the unknowns were correctly identified.

Exploring Chemical Equilibrium with Poker Chips: A General Chemistry Laboratory Exercise

A hands-on laboratory exercise at the general chemistry level introduces students to chemical equilibrium through a simulation that uses poker chips and rate equations. More specifically, the exercise allows students to explore reaction tables, dynamic chemical equilibrium, equilibrium constant expressions, and the equilibrium constant based on rate constants. Poker chips are used to simulate the reactants and products of two reversible elementary reactions.