Stoichiometry of reactions in aqueous solutions

Distinguish between an electrolyte and a nonelectrolyte, and provide examples of each. 5.2 Use the solubility guidelines tor common ionic solids to determine whether 5-4 Oxidation-Reduction Reactions Some General Principles 5-7 Stoichiometry of Reactions in Aqueous Solutions Titrations... 

Stoichiometry of Reactions in Aqueous Solutions Titrations— A common laboratory technique applicable to precipitation, acid-base, and redox reactions is titration. The key point in a titration is the equivalence point, which can be observed with the aid of an indicator. Titration data can be used to establish a solution s molarity, called standardization of a solution, or to provide other information about the compositions of samples being analyzed. 

Now that we have discussed the concentration and dilution of solutions, we can examine the quantitative aspects of reactions in aqueous solution, or solution stoichiometry. Sections 4.6. 8 focus on two techniques for studying solution stoichiometry gravimetric analysis and titration. These techniques are important tools of quantitative analysis, which is the determination of the amount or concentration of a substance in a sample. 

Earlier treatment of reactions in aqueous solution a number of our users and non-user reviewers told us that they wanted students to learn about this topic before stoichiometry. Chapter 9 addresses this request. We now have a two-chapter treatment of chemical reactivity with a qualitative emphasis, preceding the quantitative chapter on stoichiometry. Chapter 8 provides an introduction to chemical reactivity, with an emphasis on writing and balancing chemical equations and recognizing reaction types based on the nature of the equation. After students have become confident with the fundamentals, we then increase the level of sophistication of our presentation on chemical change by introducing solutions of ionic compounds and net ionic equations. 

The oxalyl radical anion decomposes to a carbon dioxide radical anion and to carbon dioxide according to Eq. 5-14. Again, the CO radical anion is able to reduce ferrioxalate with formation of ferrous ions (Eq. 5-15). The correct reaction stoichiometry of the photolysis of ferrioxalate in aqueous solution is given by Eq. 5-16 (Hislop and Bolton, 1999). 

We will now deal with the stoichiometry of acid-base reactions in aqueous solutions. The procedure is fundamentally the same as that used previously. 

The early chapters in this book deal with chemical reactions. Stoichiometry is covered in Chapters 3 and 4, with special emphasis on reactions in aqueous solutions. The properties of gases are treated in Chapter 5, followed by coverage of gas phase equilibria in Chapter 6. Acid-base equilibria are covered in Chapter 7, and Chapter 8 deals with additional aqueous equilibria. Thermodynamics is covered in two chapters Chapter 9 deals with thermochemistry and the first law of thermodynamics Chapter 10 treats the topics associated with the second law of thermodynamics. The discussion of electrochemistry follows in Chapter 11. Atomic theory and quantum mechanics are covered in Chapter 12, followed by two chapters on chemical bonding and modern spectroscopy (Chapters 13 and 14). Chemical kinetics is discussed in Chapter 15, followed by coverage of solids and liquids in Chapter 16, and the physical properties of solutions in Chapter 17. A systematic treatment of the descriptive chemistry of the representative elements is given in Chapters 18 and 19, and of the transition metals in Chapter 20. Chapter 21 covers topics in nuclear chemistry and Chapter 22 provides an introduction to organic chemistry and to the most important biomolecules. 

Pfeiffer, S., Gorren, ACF, Schmidt, K, Werner, ER, Hansert, B, Bohle, DS, and Mayer, B (1997). Metabolic fate of peroxynitrite in aqueous solution. Reaction with nitric oxide and pH-dependent decomposition to nitrite and oxygen in a 2 1 stoichiometry. 7B/o/ Chem 272(6) 3465-3470. 

In Chapter 2 we studied composition stoichiometry, the quantitative relationships among elements in compounds. In this chapter as we study reaction stoichiometry— the quantitative relationships among substances as they participate in chemical reactions—we ask several important questions. How can we describe the reaction of one substance with another How much of one substance reacts with a given amount of another substance Which reactant determines the amounts of products formed in a chemical reaction How can we describe reactions in aqueous solutions ... 

To study solution stoichiometry, we must know how much of the reactants are present in a solution and also how to control the amounts of reactants used to bring about a reaction in aqueous solution. 

Chapter 10 Reattions in Aqueous Solutions I Acids, Bases, and Salts) and Chapter 11 (Reactions in Aqueous Solutions II Calculations) include comprehensive discussions of acid-base and redox reactions in aqueous solutions and solution stoichiometry calculations for acid-base and redox reactions. 

The quantitative aspects of acid-base chemistry obey the principles Introduced earlier in this chapter. The common acid-base reactions that are important in general chemistry take place in aqueous solution, so acid-base stoichiometry uses molarities and volumes extensively. Example Illustrates the essential features of aqueous acid-base stoichiometry. 

The first step In balancing a redox reaction is to divide the unbalanced equation into half-reactions. Identify the participants in each half-reaction by noting that each half-reaction must be balanced. That Is, each element In each half-reaction must be conserved. Consequently, any element that appears as a reactant In a half-reaction must also appear among the products. Hydrogen and oxygen frequently appear in both half-reactions, but other elements usually appear In just one of the half-reactions. Water, hydronium ions, and hydroxide ions often play roles In the overall stoichiometry of redox reactions occurring in aqueous solution. Chemists frequently omit these species in preliminary descriptions of such redox reactions. 

Xenon trioxide is reduced in aqueous solution, in a thermal reaction by Pu(III) and photochemically by Np(V). The stoichiometry of the Pu(III) reduction is... 

BODIPY 530/550 C3 is insoluble in aqueous solution, but it may be dissolved in DMF or DMSO as a concentrated stock solution prior to addition of a small aliquot to a reaction. Coupling to amine-containing molecules may be done using the EDC/sulfo-NHS reaction as discussed in Chapter 3, Section 1.2 (Figure 9.29). However, modification of proteins with this fluorophore probably won t yield satisfactory results, since BODIPY fluorophores are easily quenched if substitutions on a molecule exceed a 1 1 stoichiometry. For labeling molecules which contain only one amine group, such as DNA probes modified at the 5 end to contain an amine (Chapter 27, Section 2.1), BODIPY 530/550 C3 will give intensely fluorescent derivatives. 

Lifetime of nitric oxide is an important parameter of its reactivity. Measurement of NO in intact tissue yielded a value in the order of 0.1 s [35] although preliminary estimates gave a much bigger lifetime. It has been accepted that the main reason for the rapid disappearance of NO in tissue is its reaction with dioxygen, which proceeds in aqueous solution with the following overall stoichiometry ... 

---