SOME SIMPLE PATTERNS OF CHEMICAL REACTIVITY

Symbols indicating the physical state of each reactant and product are often shown in chemical equations. We use the symbols (g), (/), (s), and (aq) for gas, liquid, solid, and aqueous (water) solution, respectively. Thus, Equation 3.4 can be written 

Sometimes the conditions under which the reaction proceeds appear above or below the reaction arrow. The symbol A (Greek uppercase delta) above the arrow indicates addition of heat. 

Begin by counting each kind of atom on the two sides of the arrow. There are one Na, one O, and two H on the left side, and one Na, one O, and three H on the right. To increase the number of H atoms on the left, let s try placing the coefficient 2 in front of H2O  

Although beginning this way does not balance H, it does increase the number of reactant H atoms, which we need to do. (Also, adding the coefficient 2 on H2O unbalances O, but we will take care of that after we balance H.) Now that we have 2 H2O on the left, we balance H by putting the coefficient 2 in fiont of 

Balancing H in this way brings O into balance, but now Na is unbalanced, with one Na on the left and two on the right To rebalance Na, we pul the coefficient 

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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. 

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