Chemical Experiments Research Articles

Advantages of assimilating multispectral satellite retrievals of atmospheric composition: a demonstration using MOPITT carbon monoxide products

Abstract. The Measurements Of Pollution In The Troposphere (MOPITT) is an ideal instrument to understand the impact of (1) assimilating multispectral and joint retrievals versus single spectral products, (2) assimilating satellite profile products versus column products, and (3) assimilating multispectral and joint retrievals versus assimilating individual products separately. We use the Community Atmosphere Model with chemistry with the Data Assimilation Research Testbed (CAM-chem+DART) to assimilate different MOPITT carbon monoxide (CO) products to address these three questions. Both anthropogenic and fire CO emissions are optimized in the data assimilation experiments. The results are compared with independent CO observations from TROPOspheric Monitoring Instrument (TROPOMI), the Total Carbon Column Observing Network (TCCON), NOAA Carbon Cycle Greenhouse Gases (CCGG) sites, In-service Aircraft for a Global Observing System (IAGOS), and Western wildfire Experiment for Cloud chemistry, Aerosol absorption and Nitrogen (WE-CAN). We find that (1) assimilating the MOPITT joint (multispectral; near-IR and thermal IR) column product leads to better model–observation agreement at and near the surface than assimilating the MOPITT thermal-IR-only column retrieval. (2) Assimilating column products has a larger impact and improvement for background and large-scale CO compared to assimilating profile products due to vertical localization in profile assimilation. However, profile assimilation can outperform column assimilations in fire-impacted regions and near the surface. (3) Assimilating multispectral and joint products results in similar or slightly better agreement with observations compared to assimilating the single spectral products separately.

Development and evaluation of immersive VR laboratories of organic chemistry and physics for students education

In science education, the use of laboratory experiments has a critical role. However, experiments can cause excessive material waste, and safety issues must be taken seriously. Virtual laboratories and simulations have become a useful and effective alternative to in-person, hands-on laboratories as a result of the educational possibilities afforded by information and communication technology. With virtual reality (VR), students can depict scientific phenomena through virtual practical experiments that use computer simulation. In this work, VR-based lab simulations of physics and chemistry experiments were introduced. Chemistry lab includes 3 experiments from organic chemistry (identify aldehydes using Tollen’s test, identify ketones using the 2,4-dinitrophenyl hydrazine test, and identify carboxylic acids using the sodium carbonate test) and physics lab includes 2 experiments on series and parallel current, accomplished through the use of the real-time 3D graphics and pre-rendered animations. Further, to assess the usability of the developed system, 20 students were surveyed as research subjects and they filled out the SUS survey after conducting the VR experiments in Oculus Quest 2. . The average score for the VR chemistry lab simulations was 92.63%, and, the average score for the physics lab was 93.38%, indicating a high level of performance and achievement among the participants. Further, in the comparative study evaluating knowledge retention and learning experience, the experimental group (VR, N=20) outperformed the control group (traditional, N=13), indicating a more favorable learning experience. All participants from the experiment group reported that virtual labs were easy to use. Overall, findings from the Knowledge Retention survey show that interactive laboratory activities enhance students’ understanding of chemical processes and practical skills.

Learning Outcomes of the Inquiry-in-Action Model for Chemistry Experimentation

There is overwhelming evidence supporting the decline of science education in Liberia. In an effort to contribute to the solution, we conducted a study to examine the impact of inquiry-based experimentation and conventional demonstration on the conceptual understanding of solutions and solubility among grade eleven students. We also investigated the relationship between students' achievement scores in solutions and solubility and their science inquiry process skills. A cluster random sample of eight schools was initially selected from 12 out of 31 high schools that had the necessary space and materials for experimentation. Using a Non-equivalent control group research design, the experimental group received instruction using inquiry-based experimentation, while the control group received instruction using traditional demonstration methods, for a period of six weeks. The results were analyzed using the Mann-Whitney U, and Wilcoxon Signed Rank tests. The findings indicated that inquiry-based experimentation reduced students' anxiety and increased their confidence in chemistry experiments. Although the inquiry-in-action model enhanced learners' conceptual understanding of solutions and solubility, it did not significantly improve their mastery of the mathematical components of the test. However, it did significantly enhance students' science inquiry process skills. It should be noted that while the inquiry-in-action model positively influenced learners' attitudes toward their preferences, behavior, and anxieties in chemistry experiments, it also led to a general demotivation to learn chemistry through experimentation. Additionally, there was a positive correlation between students' attitudes toward teaching and learning chemistry through experiments and their science inquiry process skills. However, this correlation was stronger between students' attitudes towards the demonstration of experiments and their science inquiry process skills compared to the attitudes towards the inquiry-in-action model and science inquiry process skills. This suggests that the traditional demonstration method is not entirely ineffective, and a combination of both demonstration and inquiry-based experimentation approaches may be a viable way to maximize the benefits of science experiments.

Selecting measurement subject workers for evaluation using a personal sampling method: a case involving analytical chemistry experiments at a university laboratory

Selecting measurement subject workers for evaluation using a personal sampling method: a case involving analytical chemistry experiments at a university laboratory

Exploring the frontiers of condensed-phase chemistry with a general reactive machine learning potential.

Atomistic simulation has a broad range of applications from drug design to materials discovery. Machine learning interatomic potentials (MLIPs) have become an efficient alternative to computationally expensive ab initio simulations. For this reason, chemistry and materials science would greatly benefit from a general reactive MLIP, that is, an MLIP that is applicable to a broad range of reactive chemistry without the need for refitting. Here we develop a general reactive MLIP (ANI-1xnr) through automated sampling of condensed-phase reactions. ANI-1xnr is then applied to study five distinct systems: carbon solid-phase nucleation, graphene ring formation from acetylene, biofuel additives, combustion of methane and the spontaneous formation of glycine from early earth small molecules. In all studies, ANI-1xnr closely matches experiment (when available) and/or previous studies using traditional model chemistry methods. As such, ANI-1xnr proves to be a highly general reactive MLIP for C, H, N and O elements in the condensed phase, enabling high-throughput in silico reactive chemistry experimentation.

A Mixed Reality-Based Chemistry Experiment Learning System to Facilitate Chemical Laboratory Safety Education

A Mixed Reality-Based Chemistry Experiment Learning System to Facilitate Chemical Laboratory Safety Education

Application of α-bromination reaction on acetophenone derivatives in experimental teaching: a chemical innovation experiment engaging junior undergraduates

The α-bromination reaction of carbonyl compounds is a significant topic in the field of organic chemistry. However, due to the lack of suitable brominating reagents, the application of this reaction in undergraduate organic chemistry experiments is limited. In this study, three junior undergraduates successfully conducted an innovative experiment under the guidance of teachers. The bromination of various acetophenone derivatives was investigated by employing pyridine hydrobromide perbromide as the brominating agent, with a focus on exploring the effects of reaction time, reaction temperature, and dosage of the brominating agent. The results demonstrated that 4-chloro-α-bromo-acetophenone could be synthesized at 90 ℃ using 4-chloroacetophenone as a substrate and acetic acid as a solvent with a molar ratio of substrate to brominator being 1.0:1.1. Through the experimental teaching of 18 junior undergraduates, it was observed that all the students successfully completed the experiment within a time frame of 4–5 h, with a notable achievement yield exceeding 80% observed in 14 students. This innovative experiment exhibits significant advantages in terms of safety, high yield, cost-effectiveness, and repeatability. Furthermore, while reinforcing fundamental skills in chemistry experimentation among students, it enhances their scientific literacy levels and fosters innovation consciousness as well as practical aptitude. Consequently, this approach is highly suitable for widespread implementation and integration into undergraduate experimental pedagogy.

A Modular Robotic Platform for Biological Research: Cell Culture Automation and Remote Experimentation

Robotic arms are now commonplace in diverse settings and are poised to play a crucial role in automating laboratory tasks. However, biological experiments remain challenging for automation due to their dependence on human factors, such as researchers’ skills and experience. This article introduces robotic automation and remote control for both general and biological research tasks through a modularized platform comprising a robotic arm, auxiliary tools, and software. This platform facilitates fully automated or remote execution of key experiments in chemistry and biology, including liquid handling, mixing, cell seeding, culturing, and genetic manipulation. The robot interfaces seamlessly with standard laboratory equipment and operates remotely in real time through an online program. Integration of a vision system via robotic arm webcams ensures precise positioning and object localization, enhancing accuracy. This modularized robotic platform signifies a substantial advancement in lab automation, promising enhanced efficiency, reproducibility, and scientific progress compared to human‐led experiments.

Atmospheric solids analysis probe mass spectrometry: An easy bolt-on for the synthetic undergraduate teaching laboratory.

High costs and student numbers can often hinder implementation of mass spectrometry (MS) in the undergraduate teaching laboratory, often with technicians running samples on students' behalf, and the implementation of MS only in discrete or isolated experiments. This study explores the use of atmospheric solids analysis probe MS (ASAP-MS) as a relatively low-cost, benchtop instrument, and its potential for application as a 'bolt-on' to existing undergraduate organic chemistry experiments. Thirteen products synthesised in undergraduate laboratory experiments were analysed by ASAP-MS, along with their starting materials. Analysis was carried out with a Waters RADIAN ASAP mass spectrometer, at four different cone voltages simultaneously to provide fragmentation information. Out of the 13 undergraduate experiments, ASAP-MS was shown to be complementary in 11 of these, either through simple analysis of the precursor ion or by a more complex analysis of the fragments. ASAP-MS provided spectra that both complement and enhance intended learning outcomes in existing organic chemistry experiments, showing its versatility as a bolt-on technique. Moving forward, ASAP-MS will be integrated into the University of Surrey's undergraduate teaching laboratory.

Utilization of Tamarind Seed Biocoagulant as Learning Material for Water Purification Practicum in Colloidal System

Discharging wastewater directly into the environment can harm nearby organisms. Efforts to increase environmental awareness, especially about sewage, can be started with educational activities. The study investigates the correlation between chemistry material and water purification using tamarind seed bio coagulant, assessing its feasibility for chemistry experiment design in schools. This research uses descriptive qualitative research. This study described data from observations of water purification using tamarind seedcoagulant, literature studies on chemistry practicum, and interviews with two chemistry teachers and two high school students.The results showed that the relationship between colloidal material and the experiment was to determine the types of products that contain colloidal systems in daily life and the properties of colloids. The results of the chemical parameter test revealed significant changes in the pH levels of river, laundry, and batik wastewater samples, with batik coloring waste showing the most significant changes. The organoleptic test results revealed significant changes in the color, odor, and sediment of batik dyeing wastewater. The protein in tamarind seeds can destabilize substances that cause turbidity. Based on literature studies and interviews, tamarind seed bio coagulant is feasible as a teaching material for chemistry practicum on colloidal system.

Understanding the Nature of Vibro-Polaritonic States in Water and Heavy Water.

Very recent experiments on vibrational strong coupling tend to modify chemical reactivity, energy transfer, and many other physical properties of the coupled system. This is achieved without external stimuli and is very sensitive to the vibrational envelope. Water is an excellent vibrational oscillator, which is being used for similar experiments. However, the inhomogeneously broad OH/OD stretching vibrational band make it complicated to characterize the vibro-polaritonic states spectroscopically. In this paper, we performed vibrational strong coupling and mapped the evolution of vibro-polaritonic branches from low to high concentration of H2 O and measured the on-set of strong coupling. The refractive index dispersion is correlated with the cavity tuning experiments. These results are further compared with transfer matrix simulations. Simulated data deviate as noted in the dispersion spectra as the system enters into ultra-strong coupling due to enhanced self-dipolar interactions. Hopfield coefficients calculation shows that even at ±400 cm-1 detuning, the vibro-polaritonic states still possess hybrid characteristics. We systematically varied the concentration of H2 O and mapped the weak, intermediate, and strong coupling regimes to understand the role of inhomogeneously broad OH/OD stretching vibrational band. Our finding may help to better understand the role of H2 O/D2 O strong coupling in the recent polaritonic chemistry experiments.

Nitrate Radicals Suppress Biogenic New Particle Formation from Monoterpene Oxidation.

Highly oxygenated organic molecules (HOMs) are a major source of new particles that affect the Earth's climate. HOM production from the oxidation of volatile organic compounds (VOCs) occurs during both the day and night and can lead to new particle formation (NPF). However, NPF involving organic vapors has been reported much more often during the daytime than during nighttime. Here, we show that the nitrate radicals (NO3), which arise predominantly at night, inhibit NPF during the oxidation of monoterpenes based on three lines of observational evidence: NPF experiments in the CLOUD (Cosmics Leaving OUtdoor Droplets) chamber at CERN (European Organization for Nuclear Research), radical chemistry experiments using an oxidation flow reactor, and field observations in a wetland that occasionally exhibits nocturnal NPF. Nitrooxy-peroxy radicals formed from NO3 chemistry suppress the production of ultralow-volatility organic compounds (ULVOCs) responsible for biogenic NPF, which are covalently bound peroxy radical (RO2) dimer association products. The ULVOC yield of α-pinene in the presence of NO3 is one-fifth of that resulting from ozone chemistry alone. Even trace amounts of NO3 radicals, at sub-parts per trillion level, suppress the NPF rate by a factor of 4. Ambient observations further confirm that when NO3 chemistry is involved, monoterpene NPF is completely turned off. Our results explain the frequent absence of nocturnal biogenic NPF in monoterpene (α-pinene)-rich environments.

Arsenate and phosphate adsorption onto Mg-Fe layered double hydroxides: The charge-distribution multisite complexation (CD-MUSIC) modeling as a tool to predict competitive oxyanion behavior

The adsorption of arsenate and phosphate onto natural or synthetic layered double hydroxides (LDHs) has emerged as a promising solution to minimize the environmental effects of these compounds in soils and waters. In the present work, the adsorption of these oxyanions onto Mg-Fe LDHs in both single-ion and competitive systems was studied through wet chemistry experiments, solid-state analyses, and advanced surface complexation modeling (SCM). The Mg-Fe LDH showed a good efficiency to remove both As and P, being the pH of the system a major driver for the adsorption levels observed. Adsorption results for competitive systems showed a decrease for both oxyanions compared to the single-ion adsorption systems. The adsorption behavior is mechanistically described using two types of SCM, namely the diffusion layer model (DLM) and the charge-distribution multisite complexation model (CD-MUSIC). The later model captures better the influence of pH and ionic strength on the adsorption of arsenate and phosphate onto LDH in both single-ion and multicomponent systems. The best description of the experimental results was obtained when combining two types of surface complexes, namely monodentate inner-sphere complex at lower pH values and monodentate outer-sphere complex at higher pH values. This model approach provides more detailed information about the surface properties of LDHs, which may be beneficial for future studies dealing with LDHs as reactive phases influencing metal(loid) mobility in water or soil systems.

Exploration and Practice of Independent Design Experiments in Inorganic and Analytical Chemistry: A Case Study of “Preparation and Composition Analysis of Tetraammine Copper(II) Sulfate”

Exploration and Practice of Independent Design Experiments in Inorganic and Analytical Chemistry: A Case Study of “Preparation and Composition Analysis of Tetraammine Copper(II) Sulfate”

Reform and Exploration of Integrating Artificial Intelligence Technology into “Medical Chemistry Experiment” Course under the New Engineering Background

Reform and Exploration of Integrating Artificial Intelligence Technology into “Medical Chemistry Experiment” Course under the New Engineering Background

Synthesis and Application of Decanedioic Acid-N-Hydroxysuccinimide Ester: Exploration of Teaching Reform in Comprehensive Applied Chemistry Experiment

Synthesis and Application of Decanedioic Acid-N-Hydroxysuccinimide Ester: Exploration of Teaching Reform in Comprehensive Applied Chemistry Experiment

Kinetic Resolution Enabled by Photoexcited Chiral Copper ComplexMediated Alkene <i>E</i>→ <i>Z</i> Isomerization: A Comprehensive Chemistry Experiment for Undergraduate Students

Kinetic Resolution Enabled by Photoexcited Chiral Copper ComplexMediated Alkene <i>E</i>→ <i>Z</i> Isomerization: A Comprehensive Chemistry Experiment for Undergraduate Students

ChemGymRL: A customizable interactive framework for reinforcement learning for digital chemistry

Demonstration of a new open source Python library for simulating chemistry experiments as a gymnasium-API, reinforcement learning environment. Allowing learning policies for material design tasks or pipelines using a modular, extendable design.

Laying the Groundwork for General Chemistry Experiment Teaching: Exploration and Summary of Assisting Experiment Preparatory Work through Online and Offline Integration

Laying the Groundwork for General Chemistry Experiment Teaching: Exploration and Summary of Assisting Experiment Preparatory Work through Online and Offline Integration

A Green Chemistry Experiment on Electrochemical Synthesis of Benzophenone

A Green Chemistry Experiment on Electrochemical Synthesis of Benzophenone