Physical Quantities and their Changes: Difficulties and Perceptions by Chemistry Students

The Case for Reform of the Undergraduate General Chemistry Curriculum

Like the other subjects in the science curriculum, the physical chemistry course is beset by a plethora of new findings, ideas, and areas of investigation which could, and in some cases should, be included in the course of study. However, this expansion of the breadth of the subject matter can lead to a superficial survey course which provides students with few skills and little insight which can be applied to other subjects. Abolition of the physical chemistry course and integration of its conceptual material with descriptive chemistry is one solution that has been offered for this problem. A preferable procedure is to examine carefully the meaning and use of physical chemistry, and accordingly to restructure the course so that it provides students with an introduction to and training in the use of those concepts and techniques which are of widest applicability and most lasting value. I am addressing the problem of the role, position and nature of the instruction in physical chemistry in the undergraduate curriculum. Naturally, I would not be doing this unless I thought that something is now wrong, or at the very least that we are capable of much more effective instruction than we now provide. In the following, I shall state what I feel the problems are, then discuss some possible solutions, and attempt to predict their consequences. Like the other subjects in the science curriculum, physical chemistry is becoming almost overwhelmed by new experimental findings and ideas. Many of these are more than just interesting, they are so general and important that each chemistry student should have a basic understanding of them. What has been the result of this information explosion? First, the textbooks have grown in length, and the pace of instruction has increased. Also, subjects of lesser current interest or generality have been discarded entirely, or appear in texts and are rarely taught. A number of topics such as ionic equilibria, ideal gas laws, and elementary electrochemistry, which were prominent in texts widely used as recently as 1955, have been relegated t€ the introductory general chemistry course. In still other instances, modern ideas have led to a generality and unity of presentation which has been accompanied by a most welcome saving in instructional time and, for the fortunate, a deeper understanding of the subject. However, I feel that despite these ameliorations, the overall result of the inclusion of a vastly increasing number of topics has been to make physical chemistry a shallow survey course. Many sophisticated ideas are presented so superficially that the only thing the student carries away is a feeling that he has heard of these

The paper deals with a widespread mistake in standard textbooks--an experiment with a shift of the equilibrium in gaseous mixtures of nitrogen oxides upon abrupt compression. Any explanation of this experiment should take into account two facts: noticeable heating upon compression and extremely fast chemical reactions in the system (relaxation time is of the order of a microsecond). The paper presents experimental data on kinetics in the system approaching equilibrium and the calculations of the equilibrium mixture just after compression. The paper will be suitable for an in-class lecture activity and will be useful for teachers and students in general chemistry and physical chemistry courses (gas laws, chemical thermodynamics and kinetics).

A hands-on activity for students in general chemistry and physical chemistry courses has been designed to facilitate study of intramolecular (IntraHB) and intermolecular (InterHB) hydrogen bonding in biomolecules using luminescence. 3-Hydroxyflavone (3-HF), the backbone of all flavonols, is a promising model molecule, for it possesses an excited-state intramolecular proton transfer (ESIPT) effect that can serve as a fluorescent probe for studying many biological systems. The luminescence of 3-HF has one or two bands, whose intensities are dependent on temperature and solvent. In this activity, molecular models are used to illustrate hydrogen bonding of 3-HF in the ground state in two solvents, ethanol and hexane. Then students perform an activity to enable them to observe the luminescence of 3-HF in ethanol and in hexane, at room temperature and at 77 K, respectively, followed by discussion of the luminescence of 3-HF in ordinary filter paper. The project allows students to relate the idea of hydrogen bon...

In an ongoing effort to increase student retention and success in the undergraduate general chemistry course sequence, a fully online preparatory chemistry course was developed and implemented at a large public research university. To gain insight about the efficacy of the online course, an observational study was carried out in which student performance on final exams and performance in the subsequent general chemistry course were compared between the online cohort and a previous student cohort which completed the preparatory chemistry course in a traditional lecture format. Multiple linear regression analyses were used to compare final exam scores and general chemistry course grades between the online and in-person student cohorts, while statistically controlling for incoming student academic achievement. Results from these analyses suggest the fully online course resulted in statistically significant increases in both the preparatory chemistry final exam scores and course grades in the subsequent general chemistry course. Because the retention of less academically prepared students in STEM majors is a historical problem at the institution in which the online preparatory chemistry course was implemented, the analyses also aimed to determine if this at-risk group demonstrated similar achievement relative to the population at large. Notably, it was determined that students with the lowest incoming Math SAT scores appeared to perform better in the online course relative to the analogous group of students in the in-person course. Though the observational nature of this study does not allow for the determination of causality, these results suggest a fully online course can result in improved performance for large populations of students, without resulting in a negative achievement gap for less academically prepared students. The structure and implementation of the online course and the results from the statistical analyses will be described herein.

The development of the Visual‐Perceptual Chemistry Specific (VPCS) assessment tool is based on items that align to eight visual‐perceptual skills considered as needed by chemistry students. This tool includes a comprehensive range of visual operations and presents items within a chemistry context without requiring content knowledge to solve correctly. The VPCS was administrated to a total of 2,713 chemistry students taking general, organic, inorganic, and physical chemistry courses at a large, southeastern university over a period of three academic years. The preliminary validation process involved primarily factor analysis and Item Response Theory. A three‐factor solution was considered appropriate with the most reasonable interpretation labeling Factor 1 as a general visual‐spatial skill, Factor 2 involving multiple viewpoints (frames of reference), and Factor 3 related to memory ability. Our analysis supports an interpretation relevant to chemistry instruction that departs from previous findings where the factors obtained were viewed in terms of static or kinetic qualities (mechanical) and/or two‐dimensional versus three‐dimensional aspects. Several interpretations for the three‐factor solution are discussed as well as implications for teaching and future research. © 2014 Wiley Periodicals, Inc. J Res Sci Teach 51: 963–981, 2014

General chemistry is a gateway course that impacts the STEM trajectory of tens of thousands of students each year, and its role in the introductory curriculum as well as its pedagogical design are the center of an ongoing debate. To investigate the role of general chemistry in the curriculum, we report the results of a posthoc analysis of 10 years of archived student data (ca. 12,000 students) aimed at discovering whether taking college-level general chemistry has an impact on student performance in and progression to subsequent chemistry courses. We introduce regression discontinuity; a quasi-experimental method that originated in educational psychology and can be used to estimate causal impacts of educational treatment when ex ante randomization is not feasible. Using regression discontinuity, we estimated a positive impact of prior general chemistry coursework of about one-fourth of a letter grade in two subsequent courses, Organic Chemistry I and a physical general chemistry course for nonmajors. We a...

Determining the factors that influence success in physical chemistry can inform efforts to improve teaching methods and increase student understanding. While many studies have examined factors that influence performance in general chemistry courses, very few studies have investigated physical chemistry performance. This current study re-examines correlations to mathematics ability and previous course performance, and also investigates the correlation to homework performance, which has not yet been considered. Correlation coefficients and stepwise regression equations are calculated for the factors influencing performance and the measures of success. This study shows that mathematics ability, as described by an average mathematics grade and number of mathematics courses, is an important predictor for success in the course. In addition, homework and general chemistry performance are shown to positively influence performance in physical chemistry courses. Specific recommendations are given to incorporate these factors into the course structure and thereby improve student learning.

In an ongoing effort to increase student retention and success in the undergraduate general chemistry course sequence, a fully online preparatory chemistry course was developed and implemented at a large public research university. To gain insight about the efficacy of the online course, post-hoc analyses were carried out in which student performance on final exams, and performance in the subsequent general chemistry course were compared between the online cohort and a previous student cohort who completed the preparatory chemistry course in a traditional lecture format. Because the retention of less academically prepared students in STEM majors is a historical problem at the institution in which the online preparatory chemistry course was implemented, post-hoc analyses were also carried out to determine if this at-risk group demonstrated similar achievement relative to the population at large. Multiple linear regression analyses were used to compare final exam scores and general chemistry course grades between the online and in-person student cohorts, while statistically controlling for incoming student academic achievement. Results from these analyses suggest the fully online course led to increased final exam scores in the preparatory course (unstandardized B = 8.648, p < 0.001) and higher grades in the subsequent general chemistry course (unstandardized B = 0.269, p < 0.001). Notably, students from the lowest quartile of incoming academic preparation appear to have been more positively impacted by the online course experience (preparatory chemistry final exam scores: unstandardized B = 11.103, p < 0.001; general chemistry course grades: unstandardized B = 0.323, p = 0.002). These results suggest a fully online course can help improve student preparation for large populations of students, without resulting in a negative achievement gap for less academically prepared students. The structure and implementation of the online course, and the results from the post-hoc analyses will be described herein.

General chemistry instructors are faced with a dilemma when introducing the topic of equilibrium constants: These constants are correctly written in terms of activities, yet activity is a complex topic better treated rigorously in a physical chemistry course than superficially in a general chemistry course.

Molecular geometry can be discussed in terms of the VSEPR model at several levels of sophistication—from the empirical model to a more complete model based on the Pauli principle. It is recommended that for most first-year courses VSEPR is presented at the purely empirical level or in the form of the domain version. A more sophisticated version is discussed here, not only because it should be taught in more advanced courses, but because it is important that it is understood by instructors and textbook writers so that incorrect explanations of the VSEPR model are not given. The difficulties associated with the usual treatment of the VB and MO theories in connection with molecular geometry in beginning courses are discussed. It is recommended that the VB and MO theories should be presented only after the VSEPR model either in the general chemistry course or in a following course, particularly in the case of the MO theory, which is not really necessary for the first-year course. The Pauli principle and its importance as the fundamental basis of the VSEPR model should be presented in a higher-level course, such as a quantum mechanics or physical chemistry course, or an inorganic course, in which VSEPR has many applications, for example, in the discussion of noble gas and other high coordination number molecules.

The concept of extent of reaction was discussed many times in physical chemistry journals and books. This contribution strongly suggests the use of the extent of reaction as standard basic tool in teaching stoichiometry. The same idea was suggested several times in the past without success because the concept of extent of reaction is still not presented in the first-year general chemistry textbooks. It is also remarked that the concept of extent of reaction represents a simple example of the way of attaining a mathematization of chemistry, that is chemistry thought and made with the mathematical way of thinking, i.e. using variables, symbols and functions. Presenting the concept of the extent of reaction within the general chemistry curriculum will support successive physical chemistry courses, as these courses make extensive use of this powerful concept when teaching thermodynamics and kinetics of chemical reactions.

The main goal of this study was to examine the impact of blended learning on the academic achievement of undergraduate students in the general chemistry (CHE101) course. The participants' learners of the study were (326) learners, who were randomly split into two groups, one of which taught by using blended learning (empirical group A, n = 163) and the other which with taught by using the conventional method (control group B, n = 163). To accomplish the objectives of the study, the researchers prepared the study tool, which is an achievement test, after confirming its validity and reliability. Data analyses showed that there is a statistically significant difference among the mean scores of learners in the two study groups on the achievement test, for the benefit of empirical group learners, who taught through blended learning. Moreover, the results revealed that achievement varied according to the College of the learners in the empirical group (in favor of those students of Pharmacy and Health Sciences College). However, there is no statistically significant difference in students according to the students’ gender variable and, according to the Academic year variable. The study recommended that blended learning be used more widely to cover different sectors of education.

Described in this chapter are three undergraduate laboratory activities designed to introduce undergraduate chemistry students to scientific computing through Python and Jupyter notebooks. The activities include simulating first-order radioactive decay kinetics using random number generators in a General Chemistry course, having students calculate the entropy of a substance using specific heat capacity and enthalpy data in a first-year or intermediate-level course, and performing non-linear curve fitting of real gas data in an advanced-level physical chemistry course. None of these activities assume students have previous computer programming experience and all walk the students through simulations, loading, processing, analyzing, and visualizing data. To compensate for the lack of student programming experience, the activities leverage the Jupyter notebook code and markdown cell structure to provide additional prompting and explanation and sometimes include prewritten code. Each activity incorporates computing through a different model ranging from students simply modifying and running code to writing their own Python code. This chapter will discuss not only the activities, but lessons learned from teaching the activities and challenges faced in incorporating computing into the undergraduate chemistry curriculum.

The Impact of Supplemental Instruction on the Performance and Attitudes of General Chemistry Students