Your Results

Take the streams and follow them through the process Are the calculations correct Did the computer do what you intended Are the results reasonable  

You expect Aspen Plus to be correct, but there are two possible problems lack of convergence and poor choices of thermodynamic correlations. By using the Nd button to run your problem you will get printed information about the convergence or lack of it. Read the output You get this information from the View/Control Panel menu, too. The proper choice of thermodynamic correlation can only be determined by comparison with experimental data or with experience. (This is one reason why chemical engineers are paid a lot - for their experience.) Naturally, at this point in your career, few of you have that experience. However, you can stUl look at your mass and energy balances and see if they make sense. Every number needs to be examined. 

There are three important sources of summary information, all listed under the View menu Input Summary, History, and Report. You should look at these - you may detect an error by viewing the summaries provided there. 

Transfer the Flowsheet and Mass and Energy Balance to a Word 

Select the flowsheet by dragging the mouse from the upper-left comer to the lower-right comer. Copy the flowsheet and paste it into the application. You can also use the Print Screen key and then go to your word processing program and paste it. Use the Picture/ Crop function to select the portion of the diagram that you want displayed. The best way to capture the Stream Table is to select the entire table and paste it into Excel. This is done from the Results/Summary/Stream option. 

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Calculate the vapor pressure of water when present in a capillary of 0.1 m radius (assume zero contact angle). Express your result as percent change from the normal value at 25°C. Suppose now that the effective radius of the capillary is reduced because of the presence of an adsorbed film of water 100 A thick. Show what the percent reduction in vapor pressure should now be. 

Make the following approximate calculations for the surface energy per square centimeter of solid krypton (nearest-neighbor distance 3.97 A), and compare your results with those of Table VII-1. (a) Make the calculations for (100), (110), and (111) planes, considering only nearest-neighbor interactions, (b) Make the calculation for (100) planes, considering all interactions within a radius defined by the sum... 

Using Fig. XVIII-15, calculate (D for O atom diffusion on W(IOO) as a function of 6. Comment on your results. 

What is the % difference between your result and the result using the GAUSIAN stored parameters What is the % difference between your result and the exact result for the hydrogen atom, 0.500 hartiees Make small changes in C and Y and recalculate the energy. Is the energy a sensitive funetion of the STO parameters C/ and y, ... 

Calculate E(, G2] for the methyl cation CHj. Check your result against the value used in the section on energies of atomization and ionization in this chapter. 

It is instructive for the student to construct a rough melting point diagram (compare Section 1,13 and Fig. 1,12, 1) for mixtures of cinnamic acid and urea. Weigh out 1 00 g. each of the two finely powdered components, and divide each into ten approximately equal portions on a sheet of clean, smooth paper. Mix 4 portions of cinnamic acid (A) with 1 portion of urea B) intimately with the aid of a spatula on a glass slide, and determine the melting point (the temperature at which the mixture just becomes completely fluid is noted). Repeat the procedure for 3 parts of A and 2 parts oiB 2 parts of A and 3 parts of B and 1 part of A and 4 parts of B. Tabulate your results as follows —... 

Place 0-1 g. of the substance in a semicro test-tube (75 x 10 mm. or 100 X 12 mm.) and proceed systematically with the various solvents as detailed in Section 11,27. Finally, summarise your results, and indicate the most suitable solvent or solvents for the recrystallisation of each of the above compounds. 

Shake 1 ml. of anhydrous methyl alcohol with 1 ml. of paraffin oil. Repeat the experiment with 1 ml. of n butyl alcohol. From your results state which is the better solvent for paraffin oil (a mixture of higher hydrocarbons) and thus explain why n-butanol and higher alcohols are incorporated in pyroxylin lacquers in preference to methyl and ethyl alcohols. 

Record your results in tabular form thus ... 

Determine the density at least five times, (a) Report the mean, the standard deviation, and the 95% confidence interval for your results, (b) Eind the accepted value for the density of your metal, and determine the absolute and relative error for your experimentally determined density, (c) Use the propagation of uncertainty to determine the uncertainty for your chosen method. Are the results of this calculation consistent with your experimental results ff not, suggest some possible reasons for this disagreement. 

Considering these results, discuss the optimum conditions for the determination of Mo by this method. Express your results for the precipitant as the minimum concentration in excess, as %w/v, needed to ensure a quantitative precipitation. 

Determine the uncertainty for the gravimetric analysis described in Example 8.1. (a) How does your result compare with the expected accuracy of 0.1-0.2% for precipitation gravimetry (b) What sources of error might account for any discrepancy between the most probable measurement error and the expected accuracy ... 

Using the data from Problem 1, calculate the resolution and selectivity factors for each pair of adjacent compounds. For resolution, use both equations 12.1 and 12.21, and compare your results. Discuss how you might improve the resolution between compounds B and C. The retention time for an unretained solute is 1.19 min. 

Use these data to evaluate Tg, assuming that the latter is a true second-order transition. Compare your results with the values in Table 4.4 and comment on the agreement or lack thereof. 

Using the parameters of Table 4.2, calculate the shock temperatures of MgO to 200 GPa and compare your results with those of Fig. 4.27. 

Comment on the implications of your results (e.g. Which commodities have increased by the largest factor How have the relative costs of materials changed What are the implications for the use of polymers ). 

In what way would you expect the setting and hardening reactions in cement paste to change with temperature Indicate the practical significance of your result. 

Your process may produce wastes that cannot be treated on-site, and so must be transported off-site for treatment and disposal. Wastes of this type are usually non-aqueous liquids, sludge, or solids. Often, wastes for off-site disposal are costly to transport and to treat, and represent a third-party liability. Therefore, minimization of these wastes yields a direct cost benefit, both present and future. Measure the quantity and note the composition of any wastes associated with your process that need to be sent for off-site disposal. Record your results in a table or an appropriate spreadsheet. 

Benefits of a JHA go beyond safety. As was noted in the OSHA model, the results from your JHA ean and often do lead to areas sueh as training. Don t be surprised when your results yield an adjustment in your training program or training eourse eontent. The... 

Using the information and result of Problem 4, Calculate the Bimbaum, Inspection, Fussell-Vescly, Risk Reduction Worth Ratio, Risk Reduction Worth Increment, Risk Achievement Worth Ratio, and Risk Achievement Worth Increment for each of the components A through G. Do your results agree with the equivalences in Table 2.8-1 ... 

Whether you use an audit, a survey, or a combination of both, remember that your results provide a picture of your PSM activities as of a fixed point in time. This creates a useful point of departure for detailed planning, pointing the way toward implementation and establishing a benchmark for future measurement. 

Determine the effect of basis set on the predicted chemical shifts for benzene. Compute the NMR properties for both compounds at the B3LYP/6-31G(d) geometries we computed previously. Use the HF method for your NMR calculations, with whatever form(s) of the 6-31G basis set you deem appropriate. Compare your results to those of the HF/6-311+G(2d,p) job we ran in the earlier exercise. How does the basis set effect the accuracy of the computed chemical shift for benzene ... 

How well do your results agree with the experimental value of about 3.4 kcal-mol i Since this observation is very approximate, we will not worry about zero-point energy corrections in this exercise. 

Compare your results to the experimental values of -34.0 2 kcal mol for the lithium reaction and -3.6 .5 kcal mol" for the water dimer reaction. Use the same model chemistry as in Example 8.2 B3LYP/6-311+G(2df,2p) // B3LYP/6-31G(d). 

Solution We performed our study using the ground state geometry computed with the MP2/6-31G(d) model chemistry (your results will differ slightly if a different geometry is used). 

Calculate the difference in energy between localized and delocalized forms for ally cation, radical and anion. Does it increase, decrease or remain approximately the same with increasing number of n electrons Rationalize your result. 

Examine the HOMO-2 forphenylisocyanide. Is it directly involved in any o or K bonds If so, which bonds If not, describe where it is located. Draw a Lewis structure for the molecule which is consistent with your result. 

One after the other, examine methanol dimer and acetic acid dimer. Do the hydrogen-bond lengths in these systems differ significantly from the optimum distance in water dimer Are the hydrogen-bond angles in these compounds significantly different from those in water dimer Rationalize your results. 

Examine electrostatic potential maps for free hydronium and for hydronium complexed to three and nine water molecules hydronium+3 water and hydronium+9 water, respectively). What happens to the positive charge as more and more water molecules are involved Rationalize your result. 

Are the energies and dipole moments for the twc enantiomers of carvone (ibuprofen and limonene) the same or are they different Explain your result. 

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