Elementary Chemistry Research Articles

Physical and Elementary Chemistry Characterization of Particles PM2.5 through Scanning Electron Microscopy equipped with X-ray Scattering

Physical and Elementary Chemistry Characterization of Particles PM2.5 through Scanning Electron Microscopy equipped with X-ray Scattering

An Analytical Study of Visual Illustrations in ‎Chemistry Textbooks for the Basic Stage in ‎Jordan in Light of Educational Standards

Abstract: The purpose of this study was to determine the ‎percentage of visual illustrations in elementary chemistry ‎textbooks that meet educational standards and the degree to ‎which they vary by grade level (ninth and tenth). To achieve the ‎objectives of the study, an analysis form was designed to ‎analyze the pictures, graphics, tables, and charts. It consisted of ‎‎20 criteria distributed over five domains: realism; accuracy, ‎clarity, and color; related to objectives and content; size and ‎density; and consideration for learners. The results indicated ‎that the general average of the percentage of verification of ‎educational standards for the illustrations as a whole in the ‎chemistry textbook for the ninth grade was 94.1%, with a high ‎degree, and the standards ranged between 79% and 100%.. In ‎the tenth grade textbook, the general average of the percentage ‎of verification of educational standards for the illustrations as a ‎whole was 92.8 percent with a high degree, and the standards ‎ranged between 76% and 100%..The percentages of domains ‎that have been verified in the two textbooks are ordered as ‎follows: The domains of realism, association with aims, size ‎and density, accuracy, clarity, and color, and finally the domain ‎of learner consideration, all with high degrees.The results also ‎revealed that there was no statistically significant difference in ‎the percentage of verification of the educational standards for ‎the visual illustrations as a whole between the ninth and tenth ‎grade textbooks. At the level of domains, there were significant ‎differences between the two textbooks in the field of ‎consideration for learners in favor of the ninth grade textbook. ‎However, there were significant differences in five criteria at the ‎level of standards. Three criteria were in favor of the ninth ‎grade, namely: (the title fits with the illustration, is linked to the ‎learner's previous experiences, and gives the learner positive ‎attitudes), and two criteria were in favor of the tenth grade, ‎namely: (achieving all aims related to the concept, the ‎illustration's density of concepts and information is ‎appropriate).‎ ‎(Keywords: Chemistry Textbooks, Content Analysis, ‎Educational Standards, Illustrations, Ninth and Tenth Grades)‎

(Invited, Digital Presentation) Detailed Chemical Modeling of Solid Electrolyte Interphase Growth and Evolution

The solid electrolyte interphase (SEI) is a layer that forms at the anode-electrolyte interphase in lithium ion batteries. The layer forms due to voltage instability of the electrolyte at low anode potentials, but serves to passivate the electrolyte to protect against further uncontrolled decomposition. In theory, the SEI is self-limiting, but in reality, continued growth over the battery’s lifetime leads to capacity fade, poor rate capability, and eventually cell death. Though significant progress in recent years has improved the SEI’s function and stability, poor understanding of its most basic chemistry impedes “rational design” of SEI layers for advanced battery applications. Understanding and quantifying the elementary chemistry of the SEI is made challenging by the layer’s thickness (10s to ~100 nm), chemical sensitivity, mechanical fragility, and complex chemistry (upwards of 100 reactions have been proposed). For these reasons, These factors combine to make studying the fundamental chemistry of SEI growth and evolution a significant challenge. Both the computational tools to model the SEI’s complex chemistry and the experimental data required to validate such models are all too rare.This talk will provide an overview of recent efforts to model the fundamental electrochemistry of SEI growth and evolution. The simulations are based on a continuum-scale, finite-volume framework, and leverage the open-source software package Cantera to enable efficient simulation of arbitrarily complex electrochemical mechanisms. Simulation results, as in Figure 1, are validated against two operando measurements of the SEI grown on a non-intercalating tungsten anode: depth profiling via neutron reflectometry (NR), and SEI mass uptake data via quartz crystal microbalance with dissipation (QCM-D) taken during cyclic voltammetry cycling. Interrogation of the detailed model results provide insights into the complex phenomena controlling initial SEI growth, and validation against NR and QCM-D data identify prominent reaction pathways and key chemical species present in the SEI. Finally, we will conclude by discussing future steps, includuing transferring mechanistic insights to new scales, geometries, and chemistries, and coupling models with inputs from atomistic simulations. Figure 1

Pengembangan Permainan Kartu UNO Berbasis Web Pada Materi Kimia Unsur Berintegrasi Kearifan Lokal Madura

Learning by applying games will attract students attention. This research developed the UNO card game that used the concept of elemental chemistry, especially the main groups. Each card will have a bar code that contains information links related to the elements on the card. The product integrated with the values of Madura local wisdom. The process of making elemental chemistry UNO card media used the ADDIE development model. The trial was conducted on 25 students of class XII in one of the MA and SMA in Sampang and Pamekasan districts. The results of the validation of the UNO card for chemistry elements in the media aspect obtained an average of 96.09 (very valid) and the material aspect obtained an average of 91.70 (very valid). very good category with a value of 93 percent ease of obtaining indicators, 91 percent interest, and 87 percent usefulness. The results of the average percentage of high school students’ responses after using the elemental chemistry UNO card media obtained a very good category with an indicator value of 79 percent ease of obtaining, 80 percent interest, and 84 percent usefulness. Elementary chemistry UNO card learning media can make it easier for students to learn elemental chemistry.

Operando Characterization of the Solid Electrolyte Interphase: A Means to Validate Detailed Chemical Kinetic Modeling

The solid electrolyte interphase (SEI) is a layer that forms at the anode-electrolyte interface in lithium-ion batteries. The layer forms due to voltage instability of the electrolyte at low anode potentials but serves to passivate the electrolyte to protect against further uncontrolled decomposition. In theory, the SEI is self-limiting, but in reality, continued growth over the battery’s lifetime leads to capacity fade, poor rate capability, and eventually cell death. Though significant progress in recent years has improved the SEI’s function and stability, poor understanding of its most basic chemistry impedes “rational design” of SEI layers for advanced battery applications. Understanding and quantifying the elementary chemistry of the SEI is made challenging by the layer’s thickness (4 to ca. 100 nm), chemical sensitivity, mechanical fragility, and complex chemistry (upwards of 100 reactions have been proposed). These factors combine to make modeling the SEI's fundamental growth and evolution chemistry a significant challenge. Both the computational tools to model the SEI chemistry and the experimental data required to validate such models are all too rare.This talk will present two operando measurements of the SEI grown on a non-intercalating thin film tungsten anode: depth profiling via neutron reflectometry (NR) and SEI mass uptake data via quartz crystal microbalance with dissipation monitoring (QCM-D) taken during cyclic voltammetry cycling (Figure 1).[1,2] NR results directly observe the hypothesized two-layer SEI structure, with a thin, dense inorganic “inner” layer close to the anode and a thicker, porous organic “outer” layer closer to the electrolyte. QCM-D results show the dynamic evolution of the SEI, with heavier SEI products formed at higher potentials, followed by reactions forming lighter SEI products at lower potentials. Both techniques observe “SEI breathing,” whereby soluble SEI products exit the SEI during sweeps to more positive potentials. Interrogation of the results provides new insight into the detailed chemistry of SEI formation and evolution and a platform for validating numerical simulations of the detailed SEI chemistry. Such detailed models can identify prominent reaction pathways and key chemical species present in the SEI which, in turn, can help guide the design of thermally, mechanically, and chemically stable SEI layers for advanced batteries.[1] Rus, E.D., Dura, J.A., “In situ neutron reflectometry study of solid electrolyte interface (SEI) formation on tungsten thin-film electrodes.” ACS Appl. Mat. Int., 11(50), 2019, p. 47553—47563.[2] Lee, C.H, Dura, J.A., LeBar, A., DeCaluwe, S.C., “Direct, operando observation of the bilayer solid electrolyte interphase structure: Electrolyte reduction on a non-intercalating electrode.” J. Power Sources, 412, 2019, p. 725—735. Figure 1

USING INTERDISCIPLINARY CONNECTIONS IN TEACHING ELEMENTARY CHEMISTRY

The article uses interdisciplinary communication in teaching elementary chemistry in the course "Chemistry" in secondary schools. Materials on pedagogical research and their results.

Alkali-silica reaction (ASR) - Investigation of crystallographic parameters of natural sands by backscattered electron diffraction

abstract: This study involved analyzing several natural sands to ascertain the possible causes for distress due to ASR. The analyses were performed using the following techniques: X-ray diffractometry, accelerated mortar bar tests (AMBT), electron backscattering diffraction and elementary chemistry analyses, by FEG-SEM/EBSD/EDS. These experiments allowed identifying the presence of several mineral composites (such as microcline, anorthite, among others), as well as the microstructural-crystallographic planes of quartz (such as the Dauphiné type). From the results it could be inferred that the multiple techniques used, especially the FEG-SEM / EBSD, proved to be promising in the analysis of the ASR potential of sands for use in Portland cement mortars and concretes.

Taking "the Structure and Properties of N<sub>2</sub> Molecule" as an Example to Discuss the Design of Classroom Teaching of Elementary Chemistry

Taking "the Structure and Properties of N<sub>2</sub> Molecule" as an Example to Discuss the Design of Classroom Teaching of Elementary Chemistry

Teaching of Geoscience in the context of basic education in Brazil

Brazil has a very large territory with a peculiar geological, pedologic, and climatic situation, with many natural resources, but also with situations of geological risk. The Geoscience knowledge needed to face these challenges can be learned at school. Official documents of Brazil and of the state of Sao Paulo were surveyedto determine the contents of Geoscience in the curriculum of basic education. It was observed that the topics of Geoscience in these documents are limited and separated into various disciplines: natural sciences and geography, in elementary education, and biology, geography, chemistry, and physics in high school. The documents propose an interdisciplinary approach. With references to international documents of the International Geoscience Education Organization, Earth System Education is proposed as a unifying theme for an interdisciplinary approach, and specific training on interdisciplinary work is suggested for teachers.

APLIKASI PEMBELAJARAN BERBASIS ANDROID PADA MATERI SISTEM PERIODIK UNSUR UNTUK PENINGKATAN PEMAHAMAN KONSEP MAHASISWA

This article describe the development result of android base self learning aplication to help students reach conceptual understanding on elements periodic siystem. In form research and development, it was carred out by ADDIE model. Subject of this research is chemisry education students of IKIP Mataram who fulfill Elementary Chemistry I lectur. Based on research it was concluded that : (1) android base mobile learning media application on elements periodic system subject material was produce and operate successly wity adobe air application support. Content and design validity of this product are 81.11 % and 83.97 % successively with very aligible category. Practiotioner and small group trial subject respond are 80.83 % and 89.02 % with very eleigible cathegory; (2) this android base application was enhance students elements periodic system conceptual understanding effectively. It was proved by N-gain average of students conceptual understanding enhancment is 0.82 with high category and t-gain value (6.135) larger than ttable(tα = 0.55; dk= 9 = 2.62).

Physical chemistry education - The 2014 themed issue of chemistry education research and practice

The July 2014 issue of the Chemistry Education Research and Practice is dedicated to physical chemistry education. Major sub-themes are: the role of controversies in PC education, quantum chemistry, chemical thermodynamics (including a review of research on the teaching and learning of thermodynamics) and PC textbooks. Topics covered include: the significance of the origin of PC in connection with the case of electrolyte solution chemistry; the true nature of the hydrogen bond; using the history of science and science education for teaching introductory quantum physics and quantum chemistry; a module for teaching elementary quantum chemistry; undergraduate students’ conceptions of enthalpy, enthalpy change and related concepts; particulate level models of adiabatic and isothermal processes; prospective teachers’ mental models of vapor pressure; an instrument that can be used to identify students’ alternative conceptions regarding thermochemistry concepts; and the organization/sequencing of the major areas of PC in many PC textbooks.

A mathematical approach to chemical equilibrium theory for gaseous systems IV: a mathematical clarification of Le Chatelier’s principle

Chemical equilibrium is usually discussed via a thermodynamic treatment but this does not automatically provide enough mathematical tools to be successful. A complementary mathematical approach was developed in a series of previous papers to reveal the inner logic in equilibrium shift for gaseous systems. Le Chatelier’s principle is reconsidered with this approach and a system has been developed in order to fully address the application of this principle and the dangers of using it without due consideration. In this study it is demonstrated that, more often than not, real conceptual understanding can only be achieved through mathematical derivations which help to build a more rigorous and abstract understanding. The image of chemistry can be improved by introducing more mathematics into elementary chemistry. Real chemical education delves into curricular contents and offers deep insight into chemistry which provides crucial assistance to chemical teachers and benefits students.

The Interplay of Heat Transfer and Endothermic Chemistry Within a Ceramic Microchannel Reactor

Ceramic microchannel heat-exchanger and reactor technology is capable of achieving high performance while operating under high-temperature, corrosive, and/or oxidative environments. This work describes two computational fluid dynamics (CFD) modeling studies which examine the coupling of heat transfer and endothermic methane-steam-reforming chemistry within a ceramic microchannel reactor. These modeling tools are then applied to improve microchannel-reactor design and performance. Within the reactor, methane is converted to syngas through steam reforming; the thermal requirements for this endothermic chemistry are provided by heat transfer from hot-inert gas on adjacent layers. Fluid flow, heat transfer, and complex elementary surface chemistry are all simulated using the ANSYS FLUENT models. CFD studies reveal the substantial chemical contribution of reforming on thermal gradients across and within the reactor. Improved control of the reforming temperature is also discovered through stack-design analysis, where an odd number of inert-gas layers are found to create more-uniform reactive wall temperatures. Model results provide insight on the interplay of conjugate heat transfer and chemical kinetics in reactor design.

Characterization of Black Carbon Collected from Candle Light and Automobile Exhaust Pipe

Black carbon contributes to global warming and melting of polar ice as well as causing respiratory diseases. However, it is also an inexpensive, easily available carbon nano material for elementary chemistry experiments. In this study, black carbon samples collected from candle light and automobile exhaust pipes have been investigated to examine their compositions and surface characteristics. The observed broad G and D bands and amorphous <TEX>$sp^3$</TEX> band in their Raman spectra as well as the high intensity of the D (defect) band reveal that black carbon is principally made of amorphous graphite. The black carbon deposits in automobile exhaust pipes are apparently more amorphous, probably due to the shorter time allowed for formation of the carbonaceous matter. An exceptionally large water contact angle (<TEX>$159.7^{\circ}$</TEX>) is observed on black carbon, confirming its superhydrophobicity. The surface roughness evidently plays an important role for the contact angle much larger than that of crystalline graphite (<TEX>$98.3^{\circ}$</TEX>). According to the Sassie-Baxter equation, less than 1% the area actually in contact with the water drop.

科学 Kagaku , 究理 Kyūri /Science

科学 Kagaku, 究理 Kyūri/Science Tsukahara Togo (bio) Translated by Matthew Fargo (bio) and Jordan Sand (bio) What sort of intellectual apparatus was necessary to incorporate and develop science and technology from the Meiji era onward, both as a national policy and as something inherently foreign? The ideology accompanying the introduction of science and technology was one of consummate Enlightenment faith (keimōshugi). This trait is evident in the case of the “Kyūri Fever” that arose in early Meiji Japan. In the narrowest terms, kyūri was the word for physics in the Dutch Studies tradition. In Japan, the study of physics or kyūri had always been an inquiry into the concept of “reason” (or order) conceived on the basis of the Neo-Confucian notion of the unity of reason (ri) and spirit (ki). The word kyūri was used in Dutch Studies as the translated term for Dutch words related to the study of nature (natuurkunde) or natural philosophy. Incidentally, in Dutch Studies the word for chemistry was seimi (舎密)—a transliteration of the Dutch chemie—and the biological disciplines became the “natural sciences” (博物学, hakubutsugaku), replacing the traditional pharmacology (本草学, honzōgaku). Along these disciplinary lines, kyūri was the general term for the study of nature, and loosely corresponds to our contemporary concept of “science” (科学, kagaku). The word that came to be used for “science” in the early Meiji period—kagaku (科学)—is actually short for bunka no gaku (分科の学), or “taxonomical studies.” Both the “ka” (科) of kagaku and the “ri” (理) of rigaku originally come from Taoist concepts, and are thought to have referred to ceremonial lattices and wooden frames. “Ri” and “ka” subsequently came to mean to separate and categorize things, to arrange and classify things—basically thinking about things in terms of taxonomies of differences and similarities. The use of these words to describe the sciences is intimately related to the specialization of the sciences in Europe. A large-scale campaign to promote the sciences had to be pursued before the word kagaku could find currency in Japan. This happened in the form of a series of [End Page 109] publications on kyūri begun in 1872. Masses of “scientific enlightenment” books were published in order to spread scientific education. The person behind this campaign was none other than Fukuzawa Yukichi. All of his allies at Keiō University worked hard to make the campaign effective. Fukuzawa’s brainchild was a huge success. The campaign set off a boom for kyūri tracts. This boom went down in history as the Kyūri Fever (kyūrinetsu). It spread like a contagion, as the name suggests. It is ironic to think that science, which should be dispassionate, objective, and universal, would spread like a fever. That it would become a “fad” infecting the masses, seems a social phenomenon in complete opposition to the certainty and solidity presumed to be characteristic of scientific knowledge. Focusing on this phenomenon, I would like to take a look at the characteristics of the Japanese Enlightenment that developed at this time. Kyūri Fever was spread by books known as kyūri tracts (kyūrisho), which were published with the aim of promoting European scientific ideas. Examples of these tracts include Fukuzawa’s Illustrated Kyūri (Kyūri zukai, 1872), Nagasawa Katsuhisa’s New Kyūri (Kyūri shinpen, 1872), and Mochizuki Makoto’s Elementary Kyūri Explained (Kunmō kyūri benkai, 1872). These all became classic science primers. Basic science primers from America, England, and France were also prolifically translated. With the promulgation of the new Meiji education system in 1872, Fukuzawa’s translation and publication efforts led to a series of textbooks of similar levels and styles to those adopted as school texts. Fukuzawa’s famous An Encouragement of Learning was serialized during the years 1872-76, and his Outline of a Theory of Civilization was published in 1875. Yet it is important to note that the Fukuzawa group’s kyūri tracts are not found in the line-up of textbooks adopted under the new school system. The textbooks approved by the Ministry of Education were almost all translations of American and British materials—for example, Elementary Chemistry (Shōgaku kagakusho) and Elementary...

Do explanation formats in elementary chemistry depend on agent causality?

By setting out the grammar of event causality, as developed by Hume and Mackie, in contrast to the grammar of agent causality in the natural sciences, a kind of hybrid hierarchical format for chemical explanations is sketched. From this starting point the history of agentive concepts in chemistry is displayed as a progression from Newton’s ‘forces’, through the nineteenth century concepts of ‘affinity’ and ‘valency’ to recent theories of molecular binding in terms of the migration of electrons and protons as powerful particulars. The final stage of this development is the rewriting of chemical theory in terms of energy.

An Investigation of the Gas Phase and Surface Chemistry Active During the PECVD of nc-Silicon: A Detailed Model of the Gas Phase and Surface Chemistry

In this work we present a detailed model that is able to describe the elementary chemistry active in the gas phase and on the surface during the plasma deposition of nc-Silicon films. The model is validated by comparison with mass spectrometry data measured in situ in a low energy PECVD plasma reactor. It was found that the main growth precursors are SiH3, SiH2 and SiH radicals, with the more dehydrogenated radicals becoming dominant at high hydrogen dilution, and that during the film growth more than 90% of the surface is covered by hydrogen.

Modeling Electrochemical Oxidation of Hydrogen on Ni–YSZ Pattern Anodes

A computational model is developed to represent the coupled behavior of elementary chemistry, electrochemistry, and transport in the vicinity of solid-oxide fuel cell three-phase boundaries. The model is applied to assist the development and evaluation of charge-transfer reaction mechanisms for Ni–yttria-stabilized zirconia (YSZ) anodes. Elementary chemistry and surface transport for the Ni and YSZ surfaces are derived from prior literature. Previously published patterned-anode experiments [ J. Mizusaki et al. , Solid State Ionics , 70/71 , 52 (1994) ] are used to evaluate alternative electrochemical charge-transfer mechanisms. The results show that a hydrogen-spillover mechanism can explain the Mizusaki polarization measurements over wide ranges of gas-phase composition with both anodic and cathodic biases.

Influences of O 2 concentration on NO reduction and N 2O formation in thermal deNOx process

Flow reactor experiment and chemical kinetic modeling were carried out to evaluate the influences of oxygen concentration on NO reduction and N 2O formation during thermal deNOx process for temperatures of 1073–1473 K. Increasing oxygen concentration in the reactant gas from 0.3 to 9.3% not only reduces the NO reduction potential and N 2O emission, but also lowers and widens the “temperature window” for NO conversion and N 2O formation. Trace amount of impurity O 2 leads to the lowest NO emission at a high temperature of 1373 K with low N 2O emission. Test reveals that high molar ratio NH 3/NO suppresses the reverse effect of oxygen and brings out high percentage of NO reduction at leaner environment. Chemical kinetic simulations using 4 detailed mechanisms display differing trends in the NO and N 2O dependence on O 2 and temperature. Rota 2000 model gives the best description of our experiments, but some assumptions made in this mechanism are not fully realistic. This study provides new experimental data on the less noticed N 2O, and raises a question about the understanding of the detailed elementary chemistry on the thermal deNOx process. Further work is still required for reasonable kinetic explanations.

Optimizing Control of CSTR/Distillation Column Processes with One Material Recycle

Control system design for recycle processes that are composed of a continuous stirred tank reactor (CSTR) and a distillation column is discussed. It is shown that the reflux ratio control, which has been known to serve as a self-optimizing control for the process with the elementary chemistry A → B, can be also applied to processes with more-general types of chemistry that involves side reactions. Using the self-optimizing control as the basis, control systems that seek economically optimal operations are hierarchically constructed for example processes with different types of process chemistry. Particularly, for a process that exhibits tradeoff between product yield and separation cost, a linear model predictive controller design example is given with simulation results.