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. Laboratory experiences provide opportunities to learn skills beyond chemistry content knowledge, such as how to use scientific instrumentation appropriately, how to gather and analyze data, and how to work in a team. The acquisition of process skills, including critical thinking, problem solving, and communication, is an integral part of becoming a scientist and participating in the scientific community. As apprentice scientists, chemistry students interact with each other in a context-rich environment where the need for process skills can arise organically. This study seeks to understand the role of laboratory courses in developing process skills. Students in a first-year chemistry laboratory course used rubrics to assess their own process skills. During the course, the students also received feedback via rubrics from a teaching assistant trained in rubric use. Additionally, students reported their understanding of process skills and their perceived improvements over the course of the semester. Our results suggest that students understand group dynamics process skills such as teamwork and communication better than they understand cognitive process skills such as critical thinking and information processing. While the evidence further suggests that students improved their process skills, and students reported that they improved their process skills, they showed inconsistent abilities to self-assess and provide justification for their assessment using rubrics.

We report experiments that investigate the influence of long-range attractive forces on collisional energy loss from highly vibrationally excited molecules. State-resolved studies of energy transfer from highly vibrationally excited pyridine (μ=2.2 D) to water (μ=1.8 D) in a low-pressure environment at 298 K have been performed using high-resolution transient absorption spectroscopy of water at λ≈2.7 μm. Pyridine in its ground electronic state with 37 900 cm−1 of vibrational energy was prepared by absorption of pulsed ultraviolet light (λ=266 nm) to the S1 state, followed by rapid internal conversion to the S0 state. Collisions between vibrationally excited pyridine and water that result in rotational and translational excitation of the ground vibrationless state of H2O (000) were investigated by monitoring the populations of individual rotational states of H2O (000) at short times following pyridine excitation. The infrared probe of water was the highly allowed asymmetric stretching (000→001) transition. The nascent distribution of rotationally excited H2O (000) states is well described by a thermal distribution with a rotational temperature of Trot=770±80 K. Doppler-broadened transient linewidth measurements yield the velocity distributions of the recoiling H2O (000) molecules that correspond to center-of-mass translational temperatures of Ttrans∼515 K for all water rotational states investigated. Additionally, rate constants for energy gain in individual water states were determined, yielding an integrated rate constant of k2int=1.1×10−11 cm3 mol−1 s−1 for the appearance of H2O (000) with Erot=1000–2000 cm−1. These results are compared with previous relaxation studies of excited pyrazine (μ=0 D) with water and of excited pyridine with CO2 (μ=0 D), and the influence of electrostatic attraction on the relaxation dynamics is discussed.

General chemistry is a gateway course for most STEM majors, so student success is a priority for chemistry faculty. Providing quality information resources for students, including textbooks, is one way that instructors can support student learning. However, these resources can be prohibitively expensive for some students, causing them to opt out of purchasing a textbook or incur stress from the costs of time and money to obtain a textbook. Open educational resources (OERs) are no-cost materials, available in the public domain, that students and instructors can use to reduce the financial burden of college coursework. However, as chemistry instructors consider adopting OERs, they may be concerned about the time cost to reframe their courses around different materials, the risk of negatively impacting student learning, and whether the benefits to students outweigh those costs and risks. Although the financial benefits to students have been established, and the evidence suggests minimal risk of poor academic outcomes, the cost to instructors continues to be prohibitively high. In this study, the instructor used a commercial text as the official resource for the course and offered students a choice to use either the commercial textbook or an OER textbook. This soft adoption of OERs dramatically reduced the time cost associated with using the OER for the instructor, while providing financial benefits to students who chose the OER. To address the risk that using an OER might negatively impact student performance, we investigated the impact of student textbook choice on student performance in general chemistry, controlling for relevant academic and affective variables. We found that students using OER performed as well as students using the commercial textbook. With minimal effort, chemistry instructors can provide a no-cost alternative for students, with confidence that it will not detrimentally affect their learning.

In a recent editorial (J. Chem. Educ. 2019, 96 (2), 193–195), the chemistry community was challenged to address the need for evidence supporting the role of the chemistry laboratory in student learning in order to justify the expense and resources required for laboratory courses. We suggest that laboratory coursework offers unique learning opportunities that justify the expense and conceivably warrant greater investment. Rather than viewing the resources dedicated to laboratory coursework as excessive, we consider the affordances of smaller class sizes, higher instructor to student ratios, and the diverse learning possibilities of laboratory classrooms as worthy of increased support. We call on the chemistry community to reflect on whether our actions are consistent with our beliefs about the value of laboratory coursework.

Classical trajectory calculations were performed to simulate state-resolved energy transfer experiments of highly vibrationally excited pyrazine (E(vib) = 37,900 cm(-1)) and CO(2), which were conducted using a high-resolution transient infrared absorption spectrometer. The goal here is to use classical trajectories to simulate the supercollision energy transfer pathway wherein large amounts of energy are transferred in single collisions in order to compare with experimental results. In the trajectory calculations, Newton's laws of motion are used for the molecular motion, isolated molecules are treated as collections of harmonic oscillators, and intermolecular potentials are formed by pairwise Lennard-Jones potentials. The calculations qualitatively reproduce the observed energy partitioning in the scattered CO(2) molecules and show that the relative partitioning between bath rotation and translation is dependent on the moment of inertia of the bath molecule. The simulations show that the low-frequency modes of the vibrationally excited pyrazine contribute most to the strong collisions. The majority of collisions lead to small DeltaE values and primarily involve single encounters between the energy donor and acceptor. The large DeltaE exchanges result from both single impulsive encounters and chattering collisions that involve multiple encounters.