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Applied Chemistry and Physics
Published in Robert A. Burke, Applied Chemistry and Physics, 2020
Just as the atom is the smallest part of an element, a single element is the smallest portion of a chemical compound. Chemical compounds are made up of two or more elements covalently or ironically bonded together. Ionic bonding occurs between metals and nonmetals, and involves the exchange of electrons. Covalent bonding involves the sharing of electrons between nonmetals. Chemical compounds are represented by formulas much like elements are represented by symbols. Two basic groups of chemical compounds are formed from elements: salts and non-salts.
Processing Principles
Published in Arthur J. Kidnay, William R. Parrish, Daniel G. McCartney, Fundamentals of Natural Gas Processing, 2019
Arthur J. Kidnay, William R. Parrish, Daniel G. McCartney
Before discussing the various concepts of chemistry, the definitions of atoms, molecules, and moles are needed. Atoms are the building blocks of all matter. Molecules consist of two or more atoms in a definite structure held together by chemical bonds. For example, a water molecule, H2O, contains two hydrogen atoms and one oxygen atom. A molecule that contains two or more different kinds of atoms is a chemical compound.
Basic Principles
Published in Kathleen Sellers, Fundamentals of Hazardous Waste Site Remediation, 2018
Chemical compounds are classified as organic or inorganic. Organic compounds are based on carbon atoms (with the exception of cyanide, which is inorganic). They can be anthropogenic (man-made) or naturally occurring compounds. Inorganic compounds are non-carbon based, and commonly include metals. Whether organic or inorganic, the chemical structure of a compound determines its polarity or charge, solubility, volatility, and ability to react with other substances.
Role of surface catalyzed reaction in the flow of temperature-dependent viscosity fluid over a rotating disk
Published in Numerical Heat Transfer, Part A: Applications, 2023
Khalid Abdulkhaliq M Alharbi, Saima Riasat, Muhammad Ramzan, Seifedine Kadry
A chemical reaction is a process that results in the translation of one set of chemical substances into another. During a chemical reaction, bonds between atoms are broken and new bonds are shaped, resulting in new chemical compounds. The substances that react are called reactants, and the substances that are formed as a result of the reaction are called products. A catalyst is a substance that accelerates the rate of a chemical reaction without being expended by the reaction. Catalysts work by providing a substitute trail for the reaction to occur that has a lower activation energy, which is the least amount of energy required for the reaction to proceed. This means that the catalyst helps the reactants to overcome the energy barrier that is necessary for the reaction to occur. As a result, the reactants are able to react more quickly and efficiently in the presence of a catalyst. Catalysts are used in a wide variety of chemical reactions, including those that occur in the industry, in the environment, and in living organisms. Catalysts can be either homogeneous or heterogeneous. Homogeneous catalysts are soluble in the reaction mixture and are present in the same phase as the reactants. Heterogeneous catalysts, on the other hand, are insoluble in the reaction mixture and are present in a different phase. There are many different types of catalysts that can be used to accelerate chemical reactions. Some examples include enzymes (biological catalysts found in living organisms), precious metals (such as platinum and palladium), and various types of solid catalysts (such as zeolites and metal oxides). The use of catalysts is important in many industrial processes, as they can help to increase the efficiency and yield of chemical reactions. Catalysts can also be used to reduce the energy required for a reaction to occur, which can help to reduce greenhouse gas emissions and other environmental impacts. Researchers have shown keen interest in numerous fluid problems involving chemical reactions. Hamid et al. [26] investigated the homogeneous and heterogeneous reaction for hybrid nanofluids by incorporating the Hall effect. Shankaralingappa et al. [27] examined non-Newtonian fluid flow over an elongated sheet with thermophoretic particle deposition. Ramesh et al. [28] deliberated on the activation energy in a chemical reaction. Hayat et al. [29] deliberated the nanofluid flow considering the homogeneous-heterogeneous reactions. Hashmi et al. [30] explored the impact of homogeneous-heterogeneous reactions by using magnetized Maxwell fluid. Riasat et al. [31] studied the impact of magnetic Reynolds numbers along with homogeneous-heterogeneous reactions. Various studies concerning the chemical reaction may be found in Refs. [32–36].