Information Given by Chemical Equations

After you study this chapter, you will be able to answer these ques- 

OBJECTIVE To understand the molecular and mass information given in a balanced equation. 

Reactions are what chemistry is really all about. Recall from Chapter 6 that chemical changes are actually rearrangements of atom groupings that can be described by chemical equations. These chemical equations tell us the identities (formulas) of the reactants and products and also show how much of each reactant and product participates in the reaction. The numbers (coefficients) in the balanced chemical equation enable us to determine just how much product we can get from a given quantity of reac- 

To illustrate this idea, consider a nonchemical analogy. Suppose you are in charge of making deli sandwiches at a fast-food restaurant. A particular type of sandwich requires 2 slices of bread, 3 slices of meat, and 1 slice of cheese. We can represent making the sandwich with the following equation  

2 slices bread + 3 slices meat + 1 slice cheese 1 sandwich 

More than 10 billion pounds of methanol are produced annually. 

Suppose you work for a consumer advocate organization and you want to test a company s advertising claims about the effectiveness of its antacid. The company claims that its product neutralizes 10 times as much stomach acid per tablet as its nearest competitor. How would you test the validity of this claim  

Or suppose that after graduation you go to work for a chemical company that makes methanol (methyl alcohol), a substance used as a starting material for the manufacture of products such as antifreeze and aviation fuels and as a fuel in the cars that race in the Indianapolis 500 (see Chemistry in Focus on p. 257. You are working with an 

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Information Given by Chemical Equations Mole-Mole Relationships Mass Calculations The Concept of Limiting Reactants... 

Chemical composition analysis complementing the microstructural information obtained from EM is known as analytical EM (AEM). Important compositional variations or non-stoichiometry in a material which is seemingly phase pure or stoichiometric by the criterion of bulk diffraction techniques and compositions of surface layers can be revealed using AEM. For quantitative microanalysis a ratio method for thin crystals (Cliff and Lorimer 1975) is used, given by the equation ... 

OBJECTIVE To learn to identify the characteristics of a chemical reaction and the information given by a chemical equation. 

Another useful notion which gives information on the nature of the chemical bond is the density difference function given by the equation ... 

If the solute imdergoes any chemical changes, a reaction term must be added to Eq. 12.4. In the absence of specific rate law information, diagenetic reactions are generally assumed to be first-order with respect to the solute concentration. Thus, the one-dimensional advection-diffusion equation far a nonconservative solute is given by... 

These books will teach you how to solve and balance chemical equations, find molecular weights, how to double or triple the scale of your formula (multiplying the given formula by two or three rarely works as rates of reaction and dynamic equilibrium change much more differently as the mass of reagents and precursors are increased) and other necessary information. I would like to have included this information but it would take several decades to do so and the finished book would be longer than four holy bibles combined. With so many good chemistry books available, it would be impractical for me to- do this. 

This book outlines the basic principles needed to understand the mechanism of explosions by chemical explosives. The history, theory and chemical types of explosives are introduced, providing the reader with information on the physical parameters of primary and secondary explosives. Thermodynamics, enthalpy, free energy and gas equations are covered together with examples of calculations, leading to the power and temperature of explosions. A very brief introduction to propellants and pyrotechnics is given, more information on these types of explosives should be found from other sources. This second edition introduces the subject of Insensitive Munitions (IM) and the concept of explosive waste recovery. Developments in explosive crystals and formulations have also been updated. This book is aimed primarily at A level students and new graduates who have not previously studied explosive materials, but it should prove useful to others as well. I hope that the more experienced chemist in the explosives industry looking for concise information on the subject will also find this book useful. 

The corresponding conservation equations are less familiar, but they contain the same information as a set of independent chemical reactions. The conservation equations for a system containing Ns species are given by... 

Thermochemical equations represent ordinary chemical equations also containing information on the heats of reaction, the temperature, pressure, and state of aggregation of the substance participating in the reaction. Examples are given by... 

Information about the state of a reactant or product (whether it is present as a solid, liquid, gas, or solute) may be given in a chemical equation. The following abbreviations are used solid (s), liquid ( ), gas (g), and solute in aqueous solution (aq). An aqueous solution is a solution in water. Thus, the reaction of silver nitrate with ammonium chloride can be represented by the following equation ... 

Koelman and Hoogerbrugge (1993) have developed a particle-based method that combines features from molecular dynamics (MD) and lattice-gas automata (LGA) to simulate the dynamics of hard sphere suspensions. A similar approach has been followed by Ge and Li (1996) who used a pseudo-particle approach to study the hydrodynamics of gas-solid two-phase flow. In both studies, instead of the Navier-Stokes equations, fictitious gas particles were used to represent and model the flow behavior of the interstial fluid while collisional particle-particle interactions were also accounted for. The power of these approaches is given by the fact that both particle-particle interactions (i.e., collisions) and hydrodynamic interactions in the particle assembly are taken into account. Moreover, these modeling approaches do not require the specification of closure laws for the interphase momentum transfer between the particles and the interstitial fluid. Although these types of models cannot yet be applied to macroscopic systems of interest to the chemical engineer they can provide detailed information which can subsequently be used in (continuum) models which are suited for simulation of macroscopic systems. In this context improved rheological models and boundary condition descriptions can be mentioned as examples. 

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