Proposed exercises

l Calculate the equilibrium concentration of the reforming reaction and following feed composition (molar fraction) 0.15 Ni 0.60 H2O 0.25 C2H4. The temperature is constant at 527K at pressure of 264.2 atm. Assume principal reaction. 

2 The reaction occurs in a batch reactor and determines the specific rate constant from the following experimental data. 

Assume a second-order reaction under isothermal conditions at 25°C. The initial concentration is 3.6 x 10 mol/m.  

Reactant is fed with 30% inert (N2). The kinetics is unknown and therefore following experiments were performed in a batch reactor at constant temperature. 

Verify if the reaction rate is first or second order  

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Our approach involves a thorough grounding in the fundamentals so that the background may be used in future work. Here we present numerous solved and proposed exercises (more than 400). In each chapter, problems will be classified by level of difficulty (from 1 to 10", were 10" is the most difficult). Each chapter will have references and selected Web pages to vividly illustrate all the examples. Since this is intended to be an introductory book, some concepts will receive closer attention than others. Therefore, as mentioned, each chapter will be clearly marked according to BT. A note to students using this book we are not pretending that you will be an expert in... 

This chapter proposes exercises that can be solved using the knowledge presented in the first part of the work, that is, Chapters 1 to 7. These exercises are carried out by means of a traditional spreadsheet. A file named File 1 can be found on the www.emse.fr/ soustelle site. In this file, a worksheet corresponds to each... 

The guidelines presented are simplified and may not be sufficient for all applications. This does not mean that an axial cannot be used, because the vendors can perform a much more complex analysis and change factors that this simplified method chose to hold constant. Undoing some of these values is probably beyond the scope of most of the users. The best way to interpret a potential application is that an extra measure of care might be exercised when going out for bid. This can generate additional questions concerning the vendor s proposal. 

Are there skills within the company or organization that can develop a cost-effective program specifically for the respective department, or would it be more economical in terms of costs and the proposed timetable for implementation of the program to purchase an off-the-shelf package Caution on which route should be taken must be exercised in that in-house staff may be available in the initial programming stages but as the system becomes more developed, they may not be free due to other priorities discussed above. 

If, after assessing the various computer and software packages, the decision is made to implement the proposed maintenance system on computer rather than by manual methods caution must be exercised. Irrespective of the above-mentioned benefits, the use of a computer does not increase work output but it does provide the department with a very sound method of improving the management of the company s assets and resources. 

Finally, students can be critics of published work, and perhaps have already encountered papers in the literature with questionable features. I invite reference to the paper, On the Mechanism of Catalysis by Ribonuclease Cleavage and Isomerization of the Dinucleotide UpU Catalyzed by Imidazole Buffers [Anslyn, E. Breslow, R. J. Am. Chem. Soc. 1989, III, 4473 1482]. A useful exercise is to list any flaws. Any such criticisms can then be compared with those raised in the article, Imidazole Buffer-Catalyzed Cleavage and Isomerization Reactions of Dinucleotides The Proposed Mechanism Is Incompatible with the Kinetic Measurements [Haim, A. J. Am. Chem. Soc. 1992,114, 8383-8388]. 

EXERCISE 11.58 Predict the product for the following reaction, and then propose a mechanism for formation of that product ... 

C19-0030. In Section Exercise, an aluminum-iron galvanic cell was proposed. Using information presented in this section, explain why this cell is unlikely to make a good batteiy. 

In principle, one may combine equilibrium and critical data in one database for the parameter estimation. From a numerical implementation point of view this can easily be done with the proposed estimation methods. However, it was not done because it puts a tremendous demand in the correlational ability of the EoS to describe all the data and it will be simply a computational exercise. 

The sequence of the main equipment items shown symbolically on the flow-sheet follows that of the proposed plant layout. Some licence must be exercised in the placing of ancillary items, such as heat exchangers and pumps, or the layout will be too congested. But the aim should be to show the flow of material from stage to stage as it will occur, and to give a general impression of the layout of the actual process plant. 

One of the most demanding exercises that scientists engage in is writing research proposals to obtain funding to support their work. Sketch out the structure of an expert system that would be able to help in this task. 

In the previous section we indicated how various mathematical models may be used to simulate the performance of a reactor in which the flow patterns do not fit the ideal CSTR or PFR conditions. The models treated represent only a small fraction of the large number that have been proposed by various authors. However, they are among the simplest and most widely used models, and they permit one to bracket the expected performance of an isothermal reactor. However, small variations in temperature can lead to much more significant changes in the reactor performance than do reasonably large deviations inflow patterns from idealized conditions. Because the rate constant depends exponentially on temperature, uncertainties in this parameter can lead to design uncertainties that will make any quantitative analysis of performance in terms of the residence time distribution function little more than an academic exercise. Nonetheless, there are many situations where such analyses are useful. 

For other cases, such as La3+ where more detail is required about the nature of the species present in solution, titration data can be computer fit to more complicated multi-equilibrium models containing Mx 1 v( OR)v forms whose stoichiometry is suggested by information gained from independent spectroscopic or kinetic techniques. One must be mindful of the pitfalls of simply fitting the potentiometric data to complex multi-component models for which there is no independent evidence for the various species. Without some evidence for the species put into the fit, the procedure simply becomes an uncritical mathematical exercise of adding and removing various real and proposed components until the goodness of fit is satisfactory. 

A few of those who spoke, however, endorsed the proposal. Our kids need fresh air and exercise, complained Betty Kelly of Hopkinton. They spend too much time as it is playing video games. This would give them someplace to go. ... 

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