chemical equations
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2021 ◽  
Vol 68 (1 Jan-Feb) ◽  
Author(s):  
Khaled Saad

This article analyzes and compares the two algorithms for the numerical solutions of the fractional isothermal chemical equations (FICEs) based on mass action kinetics for autocatalytic feedback, involving the conversion of a reactant in the Liouville-Caputo sense. The first method is based upon the spectral collocation method (SCM), where the properties of Legendre polynomials are utilized to reduce the FICEs to a set of algebraic equations. We then use the well-known method like Newton-Raphson method (NRM) to solve the set of algebraic equations. The second method is based upon the properties of Newton polynomial interpolation (NPI) and the fundamental theorem of fractional calculus. We utilize these methods to construct the numerical solutions of the FICEs. The accuracy and effectiveness of these methods is satisfied graphically by combining the numerical results and plotting the absolute error. Also, the absolute errors are tabulated, and a good agreementfound in all cases.


Author(s):  
Christopher O. Oriakhi

Chemistry in Quantitative Language is an invaluable guide to solving chemical equations and calculations. It provides readers with intuitive and systematic strategies to carry out the many kinds of calculations they will meet in general chemistry. Each chapter introduces the basic theories and concepts of a particular topic, focusing on relevant equations. Worked examples illuminate each type of problem, with carefully explained step-by-step solutions. Since chemistry problems can be presented in a number of ways, the examples include several versions of each question. To help students understand and retain the procedures, the solutions discuss not only what steps to carry out to reach solutions, but why. Additional problems, with answers, are included at the end of each chapter. The book is intended as a companion to a standard chemistry textbook, but can also be used on its own for review. Its primary audience is students in first-year college and university chemistry classes; it can also help in preparing for GCE Advanced Level, GRE subject test, AP Chemistry, MCAT and similar tests.


2021 ◽  
pp. 43-49
Author(s):  
Christopher O. Oriakhi

Chemical Equations introduces the ideas of writing and balancing chemical equations in terms of the amounts of reactants and products involved. Types of chemical reactions are covered to help students understand how to write a variety of chemical equations. General rules for writing and balancing chemical equations are provided.


Author(s):  
Vladimir Yustratov ◽  
Irina Timoshchuk ◽  
Alena Gorelkina ◽  
Natalia Gora ◽  
Nadezhda Golubeva ◽  
...  

Introduction. Whey drinks, fruit nectars, and reconstituted juices are usually based on domestic water. This water may contain various contaminants, which can interact with vitamins in fruit drinks. The research objective was to study the impact of trichloromethane, hydroxybenzene, chlorophenol, trichloroethylene, and ethylene chloride on the state of vitamins in juice products. Study objects and methods. The study featured aqueous fruit and berry concentrates, used in fruit nectar production. The control sample contained water without contaminants, while the test samples involved trichloromethane, trichloroethylene, ethylene chloride, hydroxybenzene, and chlorophenol. Capillary zone electrophoresis made it possible to determine bioactive substances (vitamins) in aqueous fruit and berry concentrates. Molecular absorption spectroscopy in visible spectrum was used to check the color intensity. Gas chromatography helped to analyze the content of contaminants. Results and discussion. The experiment tested vitamin preservation in fruit nectars based on water contaminated with trichloromethane, trichloroethylene, ethylene chloride, hydroxybenzene, and chlorophenol. Trichloromethane did not react with bioactive substances. Trichloroethylene, ethylene chloride, hydroxybenzene, and chlorophenol lowered the content of ascorbic acid, carotene, thiamine, riboflavin, choline, and pyridoxine. Depending on the organic matter, water contamination led to a decrease in carotene by 7–35%, vitamin B1 – by 10–100%, B2 – by 11–100%, B4 – by 8–45%, and B6 – by 8–100 in the finished product. The paper introduces a theoretic substantiation of the interaction between the contaminants and the bioactive substances. Conclusion. Water, contaminated with such organic substances as hydroxybenzene, chlorophenol, trichloroethylene, and ethylene chloride, proved to affect the vitamin preservation in juices, which was illustrated by chemical equations. Therefore, juice production requires preliminary water purification because toxic and cancerogenic substances can decrease the quality and food safety of the finished product.


2021 ◽  
Vol 83 (6) ◽  
pp. 382-386
Author(s):  
Jennifer Ferguson Hofeld

Photosynthesis and cellular respiration are core concepts in high school biology, as they are at the core of all living things. However, perhaps because students can’t see them happening, they very often have difficulty understanding them. Further, students often come into biology with a limited understanding of the law of conservation of matter as it relates to chemical reactions. These problems compound to create a great deal of misconceptions about these two important processes. In these lessons, I implemented the use of modeling to overcome these misconceptions and give my students a firm understanding of chemical equations, photosynthesis, and cellular respiration.


2021 ◽  
Vol 249 ◽  
pp. 03015
Author(s):  
R Liqoarobby ◽  
Sunardi ◽  
Y Suparman ◽  
K Fadilah

Oxygen plays a crucial role in aquatic ecosystem particularly for supporting aquaculture and hydropower. In freshwater, importance of oxygen is for metabolic respiration and balance for heterotrophic organisms. Oxygen is also involved in various chemical equations in which compounds influence each other. To prevent oxygen depletion, understanding the changes in DO and all interactions with other water qualities been reviewed with purposed to know aqueous systems work. Photosynthesis by phytoplankton is the main production of dissolved oxygen. Carbon dioxide as output from respiration of microorganisms and degradation of organic inputs and light as energy transformation of photosynthesis is needed in the process. The temperature level is involved as a determinant of gas solubility. There is also gas exchange from atmosphere to water as oxygen diffusion that move toward an equilibrium. However, dissolved oxygen absorption occurs in high demand in case an oxidizer in the degradation of organic matter which come into the reservoir. In eutrophic condition, the abundance of phytoplankton also requires oxygen for respiration, especially at night. The consumption of dissolved oxygen often spurs reservoir managers to monitor the input into the reservoir to build an aerator as a form of ensuring adequate dissolved oxygen circulation.


2020 ◽  
Vol 13 (12) ◽  
pp. 6447-6465
Author(s):  
David Simpson ◽  
Robert Bergström ◽  
Alan Briolat ◽  
Hannah Imhof ◽  
John Johansson ◽  
...  

Abstract. This paper outlines the structure and usage of the GenChem system, which includes a chemical pre-processor GenChem.py) and a simple box model (boxChem). GenChem provides scripts and input files for converting chemical equations into differential form for use in atmospheric chemical transport models (CTMs) and/or the boxChem system. Although GenChem is primarily intended for users of the Meteorological Synthesizing Centre – West of the European Monitoring and Evaluation Programme (EMEP MSC-W) CTM and related systems, boxChem can be run as a stand-alone chemical solver, enabling for example easy testing of chemical mechanisms against each other. This paper presents an outline of the usage of the GenChem system, explaining input and output files, and presents some examples of usage. The code needed to run GenChem is released as open-source code under the GNU license.


2020 ◽  
Vol 1 (4) ◽  
pp. 130-135
Author(s):  
Dwindi Agryanti Johar

This study discusses the equalization of chemical reactions using a system of linear equations with the Gaussian and Gauss-Jordan elimination. The results show that there is a contradiction in the existing methods for balancing chemical reactions. This study also aims to criticize several studies that say that the equalization of the reaction coefficient can use a system of linear equations. In this paper, the chemical equations were balanced by representing the chemical equation into systems of linear equations. Particularly, the Gauss and Gauss-Jordan elimination methods were used to solve the mathematical problem with this method, it was possible to handle any chemical reaction with given reactants and products.


2020 ◽  
Author(s):  
David Simpson ◽  
Robert Bergström ◽  
Alain Briolat ◽  
Hannah Imhof ◽  
John Johansson ◽  
...  

Abstract. This paper outlines the structure and usage of the GenChem system, which includes a chemical pre-processor (GenChem.py), and a simple box-model (boxChem). GenChem provides scripts and input files for converting chemical equations into differential form for use in atmospheric chemical transport models (CTMs) and/or the boxChem system. Although GenChem is primarily intended for users of the EMEP MSC-W CTM and related systems, boxChem can be run as a stand-alone chemical solver, enabling for exampleeasy testing of chemical mechanisms against each other. This paper presents an outline of the usage of the GenChem system, explaining input and output files, and presents some examples of usage. The code needed to run GenChem is released as open-source code under the GNU license.


Molecules ◽  
2020 ◽  
Vol 25 (8) ◽  
pp. 1912
Author(s):  
Andrea Školáková ◽  
Pavel Salvetr ◽  
Jindřich Leitner ◽  
Tomáš Lovaši ◽  
Pavel Novák

This work highlights new results on the synthesis of the TiAl3 intermetallic phase using self-propagating high-temperature synthesis. This method is considered a promising sintering route for intermetallic compounds. It was found that the reactions proceed in two stages. Below the melting point of aluminum, the Ti2Al5 phase forms at 450 °C after long annealing times by a direct solid-state reaction between the aluminum and titanium, and is converted consequently to TiAl3. This is a completely new finding; until now, many authors have believed in the preferential formation of the TiAl3 phase. The second stage, the self-propagating strongly exothermic reaction, proceeds above the melting point of aluminum. It leads to the formation of the TiAl3 phase accompanied by Ti2Al5 and Ti3Al phases. The reaction mechanism was shown in the form of chemical equations, which were supported by calculating Gibbs energy. Reaction temperatures (Tonset, Tmaximum, and Toffset) were determined after induction heating thanks to recording by an optical pyrometer. This finding provides completely new opportunities for the determination of activation energy at heating rates, in which common calorimeters are not able to detect a response or even measure. Now, the whole procedure will become accessible.


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