Ionic notation for equations

Oxidation-reduction reactions Oxidation number Oxidizing and reducing agents Ionic notation for equations Balancing oxidation-reduction equations... 

These equations represent expressions for the extrinsic ionic conductivity of the material as exhibited by the shortened defect notation of equation 12, showing that Na vacancies are created by doping and not primarily generated from thermal energy. 

The first partly filled skeleton equation could have been written in terms of NOJ rather than H NO). For variety in the subsequent solved problems, the neutral-compound notation will be used in the oxidation-state method, and the ionic notation in the ion-electron method. 

Most chemists are in the habit of describing reactions such as this one in terms of H rather than H30" ", even though hydrogen ions do not exist in a water solution in the same sense that sodium ions do. When an acid loses a hydrogen atom as H, the proton immediately forms a covalent bond to some other atom. In water, it forms a covalent bond to a water molecule to produce the hydronium ion. Although H3O" " is a better description of what is found in acid solutions, it is still convenient and conventional to write H in equations instead. You can think of H as a shorthand notation for H30". Therefore, the following net ionic equation is a common way to describe the net ionic equation above. 

By introducing the concept of ionic strength / , as defined in section 3.2.1.2, and by using molar notations for the concentrations, the equation for the Debye length becomes ... 

What we will do now is to deliberate on the nature of the ion exchange equilibrium behavior of a given ionic species, say A. However, note what the quantity Pi.( A(CA2)/dCA2) = Pb ft " adsorption of solute A stands for here (see notation in equations (3.3.121f-n)) ... 

These representations offer the advantage that one need not argue which of the reagents carries OH or Cl into the transition state. Since that is usually not known, this notation sidesteps the issue. From the Brpnsted-Debye-Huckel equation, we recognize that the concentration of each transition state (and therefore the reaction rate) will vary with ionic strength in proportion to the values of K for the given equation. For the first term we have... 

A mixed convention will be used in this chapter as an aid to indicate whether a given compound may be written in the ionized form. We will use Na+Cl-, Ba2+(NO )2, and similar notation, to indicate that compounds are ionic. Naturally, the compounds could be expressed by the molecular formulas, NaCl and Ba(N03)2, which works well for those who are intimately familiar with the solubility rules. We are not presenting the solubility rules since we prefer to concentrate on balancing the equations without having the distraction of investigating the solubility rules at the same time. 

When ionic salts dissolve in water, the salts dissociate to release the individual ions. The charged ions attract the polar water molecules such that a positively charged ion will be surrounded most closely by oxygen atoms of the water molecules (Fig. 1). Thus, ions are not free in solution, but interacting, or coordinating, with water molecules. The water molecules can be considered to be bound to the ion by so called coordinate bonds. For example, the hydrogen ion (H+) is hydrated to form H30+. For simplicity in chemical equations the simple H+ notation is used. 

H2O serves as a base in 17-3) and as an acid in 17-4). Note that the bare of 17-1) becomes the hydrated proton or hydronium ion, HsO, of 17-3). In the formulation of equilibrium constants, [H ] and [H30 ] are always equivalent to each other the two forms are used interchangeably in most contexts and will be so used in all ionic equilibrium problems in this book. Although the proton is indeed hydrated in aqueous solutions, the notation H is often used instead of H30 because the reader understands the fact of hydration, because he need not worry about specifying the exact extent of hydration (which exceeds one H2O per proton), and because the specific use of the hydrated formula for the proton might obscure the important fact that all ions in water are extensively hydrated. Note also that the denominator in the Ka expression in 17-3) is identical with that in 17-1) since applications of these equilibria are intended for dilute solutions, H2O is always taken to be in its standard state and therefore need not be represented by a term in the expression. Equation 17-4) avoids describing aqueous ammonia as NH4OH, a species that probably does not exist at ambient temperatures. 

In Chapter 11, we used lm as the symbol for molal-based ionic strength. In this chapter, we will use I. This simplifies the notation and corresponds to that used later in the chapter. bTable 18.1 actually gives values for A1, A, AL, Aj and Av, the constants in the Pitzer equations that we will summarize in the next section. The heading of the table relates C7 to A1, to A, etc. 

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