Significant figures, effects problem

The effects of substituents in ortho positions on the reactivity of benzene derivatives do not correlate well with the Hammett equation, as can be seen in Figure 26-3. The problem is that ortho substituents are close enough to the reaction site to exert significant proximity effects, which may be polar as well as steric in origin. Thus the enhanced acid strength of 2-nitrobenzoic acid over the 3- and 4-isomers (see Table 26-4) may be due to a polar stabilization of the acid anion by the neighboring positive nitrogen, which of course is not possible with the 3- and 4-isomers ... 

Given the table of data below for the reaction of o-diphenol oxidase with catechol, draw the Lineweaver-Burk plot and find the slope of the graph and use the value of the y-intercept (1/Vinax) to obtain the Am value. Compare that value to the reciprocal of the x-intercept where (1/V) = 0. Submit your graph along with your calculations. We will need three significant figures to compare with the data in the next problem to see flie effect of an inhibitor. 

Clearly, proximity and orientation play a role in enzyme catalysis, but there is a problem with each of the above comparisons. In both cases, it is impossible to separate true proximity and orientation effects from the effects of entropy loss when molecules are brought together (described the Section 16.4). The actual rate accelerations afforded by proximity and orientation effects in Figures 16.14 and 16.15, respectively, are much smaller than the values given in these figures. Simple theories based on probability and nearest-neighbor models, for example, predict that proximity effects may actually provide rate increases of only 5- to 10-fold. For any real case of enzymatic catalysis, it is nonetheless important to remember that proximity and orientation effects are significant. 

This problem was most effectively solved by fluorination of the HDPE pipes. A fluorinated layer thickness, one-fifth of that used for fluorinated LLDPE fuel tanks, was used initially. As can be seen from Figure 16.1, a significant... 

Examination of the effect of temperature (220°C-270°C) and the total heating time (20-45 minutes) on the thermal desorption process led us to adopt 2TO°C for 45 minutes as the optimum conditions for further studies. Assessment of the commercially available desorption systems in which there is flash heating of the sample, have shown that significant losses of some important compounds (p-ciesol, indole) occur on the surfaces of the metal connectors and sample transfer lines. It was to overcome these problems that the all silica system (Figure 2) was developed. 

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