Simple Patterns of Chemical Reactivity

This reaction is used to produce the bright flame generated by flares and some fireworks. 

A combination reaction between a metal and a nonmetal, as in Equation 3.6, produces an ionic solid. Recall that the formula of an ionic compound can be determined from the charges of its ions, ocxa (Section 2.7) When magnesium reacts with oxygen, the magnesium loses electrons and forms the magnesium ion, Mg . The oxygen gains electrons and forms the oxide ion, 0 . Thus, the reaction product is MgO. 

You should be able to recognize when a reaction is a combination reaction and to predict the products when the reactants are a metal and a nonmetal. 

Two or more reactants combine to form a single product. Many elements react with one another in this fashion to form compounds. 

A single reactant breaks apart to form two or more substances. Many compounds react this way when heated. 

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SOME SIMPLE PATTERNS OF CHEMICAL REACTIVITY We then examine some simple chemical reactions combination reactions, decomposition reactions, and combustion reactions. 

SECTION 3.2 Some Simple Patterns of Chemical Reactivity... 

The wave and pulse patterns of nonreactive separation processes, as well as the integrated reaction separation processes illustrated above, can be easily predicted with some simple graphical procedures derived from Eqs. (4) and (5). The behavior crucially depends on the equilibrium function y(x) in the nonreactive case, and on the transformed equilibrium function Y(X) in the reactive case. In addition to phase equilibrium, the latter also includes chemical equilibrium. An explicit calculation of the transformed equilibrium function and its derivatives is only possible in special cases. However, in Ref. [13] a numerical calculation procedure is given, which applies to any number of components, any number of reactions, and any type of phase and reaction equilibrium. 

In this section some basic features of nonlinear wave propagation in non-reactive and RD processes will be illustrated and compared with each other. The simulation results presented are based on simple equilibrium or non-equilibrium models [51, 65] for non-reactive separations. In the reactive case, similar models are used, assuming either kinetically controlled chemical reactions or chemical equilibrium. We focus on concentration (and temperature) dynamics and neglect fluid dynamics. Consequently, for equimolar reactions constant flows along the column height are assumed. However, qualitatively similar patterns of behavior are also displayed by more complex models [28, 57, 65] and have been confirmed in experiments [41, 59, 89, 107] for non-reactive multi-component separations. First experimental results on nonlinear wave propagation in reactive columns are presented subsequently. 

Today the technique of photolithography is a central element in microfabrication, most notably of microchips for the integrated circuits that control computers, mobile phones, and so many other accoutrements of modern life. The principle is simple enough. A mask with a pattern of holes is the template. It is placed over a silicon wafer coated with a photoresist , or resist for short, in the form of a reactive polymer. The resist is rendered insoluble in a chemical solution only after a reaction provoked by ultraviolet light. Irradiation through the mask then prints a latent image, as in photography, on the wafer surface. The wafer is treated with the solvent (the developer ). 

On the other hand, the varied panorama also illustrates the fact that different paths will in general be potentially available and the actual path followed, as well as the efficiency of the overall reaction, will depend on a host of factors such as the lifetime of the singlet and triplet excited states, their redox properties and chemical reactivity, the nature of the nucleophile/electron donor, the medium, etc. This also means that a demonstration of the mechanism is not necessarily a simple job. Steady-state kinetics is usually not snfficient for a complete picture and the contribution by spectroscopic techniques (e.g., epr) or by fast kinetic experiments (e.g., flash photolysis with UV or IR detection) depend on the convenience in detecting the intermediates. As a result, only in a small number of cases has the mechanism been worked out in detail, although the general pattern of most reported reaction has been assigned with reasonable confidence, sometimes on the basis of analogy. 

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