Answers to Study Problems

Analytical chemistry is a problem-solving science. Independent from the concrete analytical method, the course of action, called analytical process, is always very similar. The analytical process starts with the analytical question on the subject of investigation and forms a closed chain to the answer to the problem. Using a proper sampling technique a test sample is taken that is adequately prepared and then measured. The measured data are evaluated on the basis of a correct calibration and then interpreted with regard to the object under study. 

In addition to this work on charcoal- and silica-supported catalysts and on evaporated platinum films, a number of studies have been made on alumina-supported platinum catalysts (e.g., 111-114, 81,115) in which the aim has been the study of reactions at the platinum alone. In these cases, one cannot automatically dismiss the possibility of participation of the alumina support (i.e., of dual function behavior of the catalyst) because it is known that alumina may have acidic properties, particularly when retained halogen is present. In general terms, there is no immediate answer to this problem because the nature of this sort of catalyst wall be much dependent on the details of catalyst history, preparation, and use. However, there can be little doubt that in many experimental studies using plati-num/alumina, and in which the assumption has been made that the alumina support is inert, this assumption is essentially valid. For instance, one may note the inert alumina used by Davis and Venuto (111) and the justification provided by Gault et al. (116) for the inertness of the alumina used in a substantial body of previous work irrespective of whether the catalyst was... 

This book is divided into two main parts, one part dealing with reactions and chemical kinetics (Chapters 2 to 10), and the other dealing with reactors and chemical reaction engineering (Chapters 2 and 11 to 24). Each chapter is provided with problems for further study, and answers to selected problems are given at the end of the book. 

A similar system, (CH3)2C=CH X, was studied by Endrysova and Kraus (55) in the gas phase in order to eliminate the possible leveling influence of a solvent. The rate data were separated in the contribution of the rate constant and of the adsorption coefficient, but both parameters showed no influence of the X substituents (series 61). A definitive answer to the problem has been published by Kieboom and van Bekum (59), who measured the hydrogenation rate of substituted 2-phenyl-3-methyl-2-butenes and substituted 3,4-dihydro-1,2-dimethylnaphtalenes on palladium in basic, neutral, and acidic media (series 62 and 63). These compounds enabled them to correlate the rate data by means of the Hammett equation and thus eliminate the troublesome steric effects. Using a series of substituents with large differences in polarity, they found relatively small electronic effects on both the rate constant and adsorption coefficient. 

The objective of theoretical studies in this field, as in others, is to reach such a state of knowledge of the interrelations between the structures and properties of chemical compounds that it would be possible to deduce, by theoretical means, correct information concerning various properties of a compound from the mere knowledge of its structure. In principle, an answer to this problem is provided by quantum mechanics and its application to the study of physical and chemical properties of chemical compounds. In practice, however, we... 

An answer to this problem was found by studying a homologous series of inhibitors of the general formula... 

Most of the contributions in Chapter IV deal with this area of research. Commercial interest is centered on the field of silicones with defined silicon substitution patterns, molecular weight, crosslinking degree and the study of structure-property correlations. In constrast the academic interest focusses on topics that may be recognized as "old" problems, such as "silyl modified surfaces", "synthesis and reactivity of silsesquioxanes", and "luminescent silicon". The reader will find answers to these problems in this chapter. 

Instructions Read the problem below and study the diagram. For each part of the diagram, decide whether the necessary information is already GIVEN in the problem, whether you can find it by first getting a PARTIAL ANSWER, or whether you can find it as the FINAL answer to the problem. Fill each part of the diagram with one of the three choices. Click in the OKAY box when you have filled the diagram. 

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