Physical Chemistry Course Research Articles

Conceptual Changes of Students in Thermodynamics in Physical Chemistry Course Through The Implementation of Blended Learning

This study aims to determine the conceptual changes of students after participating in learning with a blended learning approach on Thermodynamics material. This research is a type of pre-experimental (pre-experimental design) with a One Group Pretest-Postest Design. The blended learning approach is applied using the Problem Based Learning model. The research sample was Class C Odd Semester 2019/2020 students which consisted of 34 students who programmed Physical Chemistry courses. The instrument used is a two-tier multiple choice test which includes concepts in Thermodynamics material which is equipped with a valid CRI. The blended learning approach is one approach that can be used that facilitates student activities in utilizing ICT through the delivery of materials, discussion of task completion, and training in the search for teaching materials on Thermodynamics material. The results showed that misconceptions still occur in every concept of Thermodynamics. The average reduction of misconceptions (MC) is 11.2%, the increase in the number of students to knowing concept (KC) classically is 19.2%, and the decrease in the number of students unknowing concept (UKC) is classically 8.1%. Students' conceptual changes to the material of Thermodynamics are still low. Students are required to understand well the content of the material related to basic concepts, mathematical equations (formulas), and the applicative forms of concepts in everyday life in accordance with the characteristics of the thermodynamic material.

Kinetics and Pathways of the Aqueous Photolysis of Pharmaceutical Pollutants: A Versatile Laboratory or Remote Learning Investigation

In this laboratory experiment, students explore the aquatic photochemical fate of ranitidine and cimetidine, two common pharmaceutical pollutants found in wastewater. It provides an engaging environmental context for students to develop knowledge of reaction kinetics and photochemistry as well as skill in using analytical instrumentation. This versatile experiment consists of two basic modules, three optional advanced modules, and additional add-ons that may be performed in various combinations to meet the unique learning objectives of general, analytical, physical, and environmental chemistry courses and science outreach activities. It may be performed as a traditional lab experiment or as an entirely remote exercise with an increased focus on data analysis and interpretation using provided example data sets. All of the photolysis experiments are carried out by preparing solutions of ranitidine or cimetidine in various matrices, irradiating the samples, and periodically removing subsamples for HPLC analysis of the compound of interest. Pseudo-first order kinetic plots are then generated to determine rate constants that are used to draw conclusions about photolysis pathways or to calculate additional kinetic parameters. In the two basic modules, cimetidine is found to degrade appreciably only when irradiated in the presence natural organic matter (NOM), indicating an indirect, photosensitized degradation pathway. In contrast, ranitidine degrades in pure buffer and in the presence of NOM with comparable rate constants, highlighting the predominant role of direct photolysis. In the advanced modules, students calculate ranitidine direct photolysis quantum yields and examine the significance of singlet oxygen as a photochemically produced reactive intermediate. The two basic modules may be completed in two 3 hour lab periods, while the advanced modules require additional time. This experiment requires only an HPLC instrument, inexpensive chemicals, and common glassware and lab equipment if performed in person and a personal computer if performed remotely.

Analysis of the Learning-Centeredness of Physical Chemistry Syllabi

Students’ negative perceptions of physical chemistry courses are well-known and are likely impacting their learning and performance in this upper-division course for majors. The syllabus can be the first interaction students have with a course and instructor and can be central to the expectations student set for the learning experience. While syllabi are not necessarily evidence of enacted classroom practice, their focus may be related to the enacted course design and instructional practices. Additionally, developing and modifying the document gives an instructor an opportunity to reflect on those same enacted practices, potentially facilitating a more learning-centered experience for students. In this study, we collected physical chemistry syllabi from across the United States and evaluated the learning-centeredness of this document using the Measuring the Promise syllabus rubric. Physical chemistry syllabi from 2017 to 2019 were largely content-focused. Analysis of the specific components of syllabi revealed potential improvements that may shift the focus of physical chemistry syllabi toward the learning end of the learning-centeredness spectrum. These include communicating learning goals and objectives across a wide range of dimensions, introducing transparency about the alignment of assessments with objectives, and creating supportive classroom climates via the syllabus.

Learning Reaction Kinetics through Sustainable Chemistry of Herbicides: A Case Study of Preservice Chemistry Teachers’ Perceptions of Problem-Based Technology Enhanced Learning

Teaching the fundamentals of chemical kinetics on the college level is challenging to teachers and students alike due to its abstract nature of concepts and limited connection with real context applications. This study consisted of two phases starting with designing a chemistry education for the sustainable development-based learning environment of reaction kinetics, followed by a case study in which students’ perceptions toward learning chemistry by solving a real environmental problem using digital resources, spreadsheets, and an active learning environment, were explored. First, we designed a Socio-Scientific Environmental Chemistry module centered on the sorption kinetic processes of herbicides in volcanic ash derived soils (VADS) and their potential to pollute groundwater. The objective of the learning module was to contribute to the development of sustainability skills, to promote learning of contextualized chemistry knowledge, and to develop scientific skills. This module employs spreadsheets as computational tools in chemistry to model real sorption kinetic data of herbicides in VADS. The learning module was designed for one section of two Analytical Chemistry courses and one Physical Chemistry course of an undergraduate chemistry teacher-training program. After the design phase, the learning module was implemented in each course, and students’ perceptions were gathered using the focus group technique. The sample was of 22 students distributed into three focus groups. The data collected were analyzed and categorized through qualitative content analysis using the Technological Pedagogical Science Knowledge (TPASK) framework. On the basis of our findings, the students acquired contextualized chemistry knowledge and develop skills and knowledge related to using digital resources and spreadsheets in a scientific context. Besides, the preservice chemistry teachers’ knowledge of pedagogy allowed them to develop some elements of their pedagogical science knowledge and TPASK. This case study shows that the problem-based learning approach offers great potential in supporting a learning environment suitable to working with spreadsheets to solve real-environment problems in chemistry education.

Computational Chemistry Activities with Avogadro and ORCA

Computational chemistry modeling activities that took place as part of a course in physical chemistry are described. The main software tools used by the students were Avogadro and ORCA, which are freely available on the Internet for academic use. Avogadro is molecular visualization software, which can be used not only to prepare input files for a range of computational chemistry software but also to visualize output files from them. ORCA is an ab initio quantum chemistry program containing modern electronic structure methods, such as density functional theory, many-body perturbation, coupled cluster, multireference methods, and semiempirical quantum chemistry methods. Four introductory level computational chemistry activities are described for use in general chemistry and physical chemistry laboratory courses and all are suitable for virtual learning environments. Details of our implementation and the educational value of this work are discussed. In addition, a Student Assessment of their Learning Gains (SALG) survey was conducted after the implementation and the results are reported.

Scholarship-Based Undergraduate Laboratory Courses Modeled on a Graduate School Research Rotation

This paper describes and assesses the impact of a new upper-level “scholarly” laboratory model that is part of a four-year scaffolded research skills curriculum at a Carnegie Bachelor’s institution. In this scholarly lab model, students gain the “tools” of a discipline in a first-semester laboratory and engage in the scholarly work of the instructor in the second semester. Analogous to the experience of graduate students in a research rotation program, undergraduates participating in these scholarship-based laboratories in addition to their capstone research requirement are exposed to chemical research in multiple subdisciplines as well as different scholarly strategies to conduct research. Student perception data show that scholarly lab students feel highly engaged in all steps of the scientific method and that they integrate, implement, and improve the research skills gained throughout the four-year research skill curriculum. Authentic, student-driven collaborations within and between courses were observed multiple times in the two pilot iterations. However, the model was less effective than anticipated at building student confidence and sense of inclusion in the scientific community. Participation in the scholarly based laboratory model led to a statistically significant ∼10% improvement in lab notebook, final presentation, overall lab, and overall course grades for the scholarly lab cohort compared to a traditional lab cohort in a second-semester physical chemistry course. College-assigned women and men benefit similarly from the scholarly lab model, though these groups show some important perception differences that are discussed.

Research Trends in Technology-Enhanced Chemistry Learning: A Review of Comparative Research from 2010 to 2019

Chemistry is a subject which involves a number of abstract concepts, making it a difficult and frustrating learning process for many students. Educators and researchers believe that technology could provide an opportunity to address this problem. However, it is challenging to find a model for appropriately and successfully integrating technology into chemistry education. Therefore, in this study, a review was conducted on the technology-enhanced chemistry learning studies published in Social Science Citation Index (SSCI) journals from 2010 to 2019. This study searched the target articles from the Web of Science (WOS) database and excluded those studies that did not adopt a comparative research design. Finally, 60 studies were included in this research trend analysis. A coding scheme was developed for the types of technology, the types of learning tools, the roles of technology in chemistry learning, learning topics, learning environments, participants, research designs, and the learning outcomes the researchers evaluated. From the analysis results, it was found that (1) inorganic chemistry and physical chemistry courses were the main learning topics, while the formal classroom was most often referred to as the research setting. The most frequently discussed issue was students’ learning achievement. (2) Regarding technology integration, offering students learning content through personal computers was the main activity mode. The technology was used for lower-level implementation, that is, providing supplementary materials for students. (3) Finally, using keyword analysis, it is possible to extract the recent concerns of the researchers, and from the results of the study, it is clear that the researchers are placing increasing emphasis on learners’ experience and skill development in the learning process. Accordingly, this study highlights the features of the research trends and then provides suggestions for researchers in the technology-enhanced chemistry learning field.

Student discourse networks and instructor facilitation in process oriented guided inquiry physical chemistry classes

A novel methodology has been developed to capture student interactions and engagement modes by mapping their discourse in Process Oriented Guided Inquiry Learning (POGIL) physical chemistry courses using graph theory and a modified ICAP (Interactive, Constructive, Active, Passive) framework. This work provides a deeply contextualized description of student teamwork in a POGIL setting with triangulation of data from talk-turn tracking and coding of student engagement. Graphs of student discussions in teams were constructed for 17 students in five teams in two courses taught by different instructors. Combined with the modified ICAP framework, our data illustrate the amount, extent, and quality of discussion along with students’ cognitive engagement. Specific facilitation strategies used by instructors appear to correlate with improved student discussion and interactivity. Such strategies include providing responsive versus prepared lectures and requiring students to publicly share their thinking.

Physical Principles of Circular Dichroism

Circular dichroism (CD) is the differential absorption of left and right circularly polarized light. It arises from molecular electron oscillations that are driven by both the light’s electric and magnetic fields, where the effects are in phase for one circular polarization and out of phase for the other. We describe these interactions, which have not been presented at an intuitive level before, with classical and quantum treatments. A rotational average of the latter solution leads to the Rosenfeld equation, which underlies most CD research. We illustrate its use with a chiral version of a harmonic oscillator, which we then apply to the far-ultraviolet CD of protein α-helices. This presentation is aimed at the level of upper-division undergraduates and could be usefully incorporated into a physical chemistry course.

The Individual Experience of Online Chemistry Teacher Education in China: Coping with COVID-19 Pandemic

The practice and research on online chemistry education have received great attention in the context of the COVID-19 pandemic worldwide. This paper describes the teaching practice of online learning based on three online courses for pre-service chemistry teachers. To adapt online teaching requirements, we reshaped the structure of the physical chemistry course, for example, adjusting the assessment approaches, and reinforcing long-distance instruction. Besides, we also shared the course of training chemistry teaching skills online publicly, and provided multiple learning approaches after class. Moreover, we introduced chemistry education research based on website data in an educational research methods course and shared ideas through the technology platform.

The Sudden Switch to Online Teaching of an Upper-Level Experimental Physical Chemistry Course: Challenges and Solutions

This communication reports the curriculum changes and how they worked when an upper-level experimental physical chemistry course had to switch from face-to-face to online teaching within a matter o...

Asynchronous Online Assessment of Physical Chemistry Concepts in the Time of COVID-19

The COVID-19 pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has disrupted normal activities all over the world. Education at all levels has been particularly hard hit, and this has resulted in the suspension of face-to-face discourse, instruction, and student assessment worldwide, with the necessity of social distancing preventing the social gatherings common to all learning environments. This has prompted a shift to online modes of teaching and assessment, with varying degrees of success and possibly much discomfort. In this communication, reflections and comments on the results of asynchronous online assessment of physical chemistry courses at the Cave Hill campus of the University of the West Indies are presented. We hope this paper will be useful in delineating some of the challenges faced in the delivery of unsupervised online assessments, especially in situations where limited internet connectivity may disadvantage some students.

Using Familiar and New Assessment Tools in Physical Chemistry Courses During COVID-19

A fast track into online teaching in response to the COVID-19 crisis resulted in the author learning to use online platforms and tools to teach thermodynamics and quantum mechanics courses. These resources were used effectively to teach highly mathematical and challenging concepts, as presented in this communication. Student assessment using traditional (exams) and novel (projects) approaches are highlighted, especially the use of projects that examined students’ ability to apply their knowledge to solve real world problems. A survey of students’ responses to online learning revealed that they felt supported during the COVID-19 crisis and the teaching tools described in this work were successful in helping them learn. These students who completed parts of the two courses in face-to-face classes in previous quarters overwhelmingly preferred in-person instruction. The pedagogical approaches described in the communication were shared informally with fellow science faculty at the college. They may be successful in teaching other chemistry courses and STEM fields. The author feels better prepared for teaching online in the future as a result of this teaching experience.

Testing in the Time of COVID-19: A Sudden Transition to Unproctored Online Exams

The swift conversion of chemistry courses to various online formats has presented challenges for students and instructors alike, with one of the most significant challenges being the logistics concerning online testing. At our institution, instructors of general, organic, and physical chemistry courses sought to balance issues of exam access, exam security, and continuity with a traditional test format when switching to unproctored online exams. Different approaches were utilized for exam delivery with varying success. Common challenges arose in several courses, such as the need to train students to use new technology, and the threat of online information for compromising exam security. The most successful attempts to meet these challenges, such as use of a test-bank, are consistent with reported best practices and suggest a way to maximize access, security, and continuity, while working to diminish technological and ethical pitfalls that accompany unproctored online exams.

CURRICULUM RENEWAL FOR BETTER DESIGN-RELATED STUDENT OUTCOMES IN SECOND-YEAR CHEMICAL AND BIOLOGICAL ENGINEERING

The Department of Chemical and Biological Engineering at UBC is currently undergoing a major curriculum renewal with the aim of modernizing the two undergraduate programs it offers to better prepare students for increasingly diverse industries. Part of this initiative aims to introduce design earlier and integrate it throughout the programs. At the core of the new 2nd year curriculum are two new courses: CHBE 220 and 221 – Fundamentals of Chemical and Biological Engineering I/II. CHBE 220 is taken in term 1 and replaces a previous classically-structured physical chemistry course and an introductory seminar on process technology. It focuses on basic chemical process design and analysis, drawing from thermodynamics and kinetics as needed to support design topics. CHBE 221, offered in term 2, replaces the previous introductory cell biology course, and focuses on industrial microbiology and bioprocess design, drawing from cell and molecular biology and physical chemistry as needed to support design tasks. Both courses include substantial term-spanning design projects. This paper outlines the content and structure of both courses and their place in the updated curriculum. It describes the integrated design projects and other course deliverables. Recommendations for future iterations of the courses are also presented.

Fundamentals of Macroscopic Chemical Analysis: A Foundation-Level Course for a New Chemistry Curriculum

Fundamentals of Macroscopic Chemical Analysis is a newly developed foundation-level course that integrates concepts from traditional physical and analytical chemistry courses. The course was designed to serve majors in chemistry, biochemistry, and biology as well as pre-health professional students. The main goal of this course is to develop the ideas of energy, stability, and direction of changes for chemical systems. Students develop the idea of free energy through thermodynamic laws and apply the concept of free energy to develop the quantitative picture of selected physical and chemical equilibrium systems.

That’s So Cool. Using a Flame to Freeze Water. The Vapor-Absorption Refrigerator and How It Works

The design and operation of the vapor-absorption refrigerator (VAR) are described using the principles and tools typically covered in upper-division undergraduate physical chemistry courses. The objective is to enable students to understand in detail how this device works and how it compares with more typical vapor-compression refrigerators. Calculations of the thermodynamics and heat flow relating to the refrigeration cycles are presented, leading to the calculation of the coefficient of performance. Two types of VARs are examined, one using LiBr/water solution as the absorbing medium and water as the refrigerant, which relies on the hygroscopic nature of aqueous solutions of LiBr. The second uses water as the absorber and ammonia as the refrigerant. The device described, the Crosley IcyBall, was a popular and inexpensive home refrigerator requiring no electricity. It is an example of a VAR operating in a single-cycle mode.

Graphical Representation of Hückel Molecular Orbitals

In this paper, we develop a general but very simple mathematical foundation for the predefined coefficient graphical method of Huckel molecular orbital theory (HMO). We first present the general solution for the recurrence relation of the coefficients of Huckel molecular orbitals (MOs). Subsequently, for all the three unbranched hydrocarbons, i.e., open-chain, cyclic Huckel and Mobius polyenes, different boundary conditions are explored for obtaining the MOs and their energy levels. The analytic continuation of the recurrence relation, in which one extends the domain from integral to real, allows us to analyze the symmetric properties of Huckel MOs in an elegant fashion without even knowing the actual expressions. In fact, we can use the symmetric properties to derive the Huckel MOs of the unbranched hydrocarbons and some branched hydrocarbons such as naphthalene. Consequently, this work also provides a pedagogical alternative to present the HMO model for students in an advanced physical chemistry course. Finally, the graphical approach could be a good mnemonic device for students’ comprehension of the HMO theory.

Choosing the adequate thermodynamic reference state: The evolution of pyrophosphate bioenergetics as an example.

The use of the thermodynamic formalism in the investigation of biochemical reactions constitutes one of the key analysis in bioenergetics, and the first step in such analysis is the selection of the adequate reference state. For biochemistry majors, thermodynamic analysis based on the chemical reference state is used in Physical Chemistry courses, while the biological and biochemical reference states are used in Biochemistry courses. As these definitions are introduced in different courses, it is difficult that students can understand the need to select a reference state as a first step in the energy analysis of a system. The lack of suitable examples in textbooks to illustrate the importance of the adequate selection of the reference state in a thermodynamic analysis, promoted the present analysis of the energetic role of pyrophosphate (PPi) in comparison with adenosine-triphosphate in different ambient conditions, namely, the early PPi world (better described by the chemical reference state), the enclosed systems like the cells (better described by the biological reference state), and the actual thioester world (better described by the biochemical reference state). This example not only provides a new interesting point of view on the evolution of two biochemical fuels but also represents a biochemical example in which the use of different reference states can illustrate a single process from different points of views.

Developing technological pedagogical science knowledge through educational computational chemistry: a case study of pre-service chemistry teachers’ perceptions

The purpose of this descriptive case study was to develop pre-service chemistry teachers’ Technological Pedagogical Science Knowledge (TPASK) through novel computational chemistry modules. The study consisted of two phases starting with designing a computational chemistry based learning environment followed by a case study where students’ perceptions towards educational computational chemistry were explored. First, we designed an authentic research-based chemistry learning module that supported problem-based learning through the utilisation of computational chemistry methods suitable for pre-service chemistry education. The objective of the learning module was to promote learning of specific chemistry knowledge and development of scientific skills. Systematic design decisions were made through the TPASK framework. The learning module was designed for a third-year physical chemistry course taken by pre-service chemistry teachers in Chile. After the design phase, the learning module was implemented in a course, and students’ perceptions were gathered using semi-structured group interviews. The sample consisted of 22 pre-service chemistry teachers. Data were analysed through qualitative content analysis using the same TPASK framework employed in the learning module design. Based on our findings, pre-service chemistry teachers first acquired Technological Scientific Knowledge (TSK) and then developed some elements of their TPASK. Besides, they highly appreciated the combination of student-centred problem-based learning and the use of computational chemistry tools. Students felt the educational computational learning environment supported their own knowledge acquisition and expressed an interest in applying similar learning environments in their future teaching careers. This case study demonstrates that learning through authentic real-world problems using educational computational methods offers great potential in supporting pre-service teachers’ instruction in the science of chemistry and pedagogy. For further research in the TPASK framework, we propose there would be significant benefit from developing new learning environments of this nature and evaluating their utility in pre-service and in-service chemistry teacher's education.