Knowing, ways

Know ways to establish your expertise as a researcher... 

It is important that you note the link between the OSO4 reaction and the stereospecific transformations that we highlighted at the beginning of Chapter 34. in particular, you now know ways to add two hydroxyl groups both syn... 

This shows us how we can determine values for or A. We will need to measure k for at least two temperatures, but we already know ways to do that. The rearranged equation is in the femiliar form of a line, y = mx + b, so z plot of In k versus 1/T should be a straight line. The line s slope is -EJR, where R is the gas constant, whose value is known. So we can get an estimate of the activation energy from the slope, as shown in Figure 11.13. This type of problem is easily attacked with a graphing calculator or a spreadsheet, and there are several such problems at the end of this chapter. 

Up until now, little has been said about time. In classical mechanics, complete knowledge about the system at any time t suffices to predict with absolute certainty the properties of the system at any other time t. The situation is quite different in quantum mechanics, however, as it is not possible to know everything about the system at any time t. Nevertheless, the temporal behavior of a quantum-mechanical system evolves in a well defined way drat depends on the Hamiltonian operator and the wavefiinction T" according to the last postulate... 

For the construction of F, we need to know how two particles can collide in such a way that one of them has velocity v after the collision. The answer to this question can be found by a more carefiil examination of the... 

We now know of the existence of over one hundred elements. A century ago, more than sixty of these were already known, and naturally attempts were made to relate the properties of all these elements in some way. One obvious method was to classify them as metals and non-metals but this clearly did not go far enough. 

The two sources of stochasticity are conceptually and computationally quite distinct. In (A) we do not know the exact equations of motion and we solve instead phenomenological equations. There is no systematic way in which we can approach the exact equations of motion. For example, rarely in the Langevin approach the friction and the random force are extracted from a microscopic model. This makes it necessary to use a rather arbitrary selection of parameters, such as the amplitude of the random force or the friction coefficient. On the other hand, the equations in (B) are based on atomic information and it is the solution that is approximate. For ejcample, to compute a trajectory we make the ad-hoc assumption of a Gaussian distribution of numerical errors. In the present article we also argue that because of practical reasons it is not possible to ignore the numerical errors, even in approach (A). 

A data set [x,y] can be represented in three ways as a tabular collection of measurements, as a graph, or as an analytical function y =f x). In the process of reducing a tabular collection of results to its analytical form, some information is lost. Although y =f x) gives us the dependence of y on a , we no longer know where the particular measurement yi at x is. That information has been lost. Often, selection of the form in which experimental results will be presented depends on how (or whether) information loss influences the conclusions we seek to reach. 

We do not know the orbitals of the electrons either. (An orbital, by the way, is not a ball of fuzz, it is a mathematical function.) We can reasonably assume that the ground-state orbitals of electrons I and 2 are similar but not identical to the Is orbital of hydrogen. The Slater-type orbitals... 

The Slater-type orbitals are a family of functions that give us an economical way of approximating various atomic orbitals (which, for atoms other than hydrogen, we don t know anyway) in a single relatively simple form. For the general case, STOs are written... 

You also know how to make acids by FGl from a primary alcohol but an acid is itself a hydroxyl compound and can be disconnected in the same way as alcohols. What do you get if you do this ... 

We must next disconnect the six-membered ring and the only way we know to set up these chiral centres specifically is by the Diels-Alder reaction. Two alternative sites for the double bond are possible if we convert our NHi to give the necessary activating group (NOi)... 

See if the software documentation suggests any other ways to change the DIIS method. You may have to run hundreds of calculations to become experienced enough with the method to know what works when and by how much to adjust it. 

This method is a little labor-intensive because it involves a lot of distilling, but it is so easy to do and the results are absolutely predictable The production of MD-P2P or P2P using this method has been previously described [8,9] except that Strike is going to describe the little things. You know, those little bullshit things that never seem to work their way into official accounts but always cause a lot of stress to the novice chemist. 

The next day comes and the hung-over chemist wakens to see a dark red solution stirring away. In some cases where the chemist had made an enormous batch of this stuff, there may be seen a small mass of crystalline precipitate at the bottom of the flask. This is no big deal and will go away in the next step. If the chemist had made this in a flat-bottomed flask (which she really should have for convenience) then the ice tray is removed, the flask returned to the stir plate, a distillation setup attached, and the acetone is vacuum distilled from the flask. After all the acetone has come over the chemist can proceed in two different ways. One way is to just keep on distilling the solution until all of the formic acid has been removed. The chemist knows that just about all the formic has been removed when there is about 300mL of thick black liquid remaining in the reaction flask and hardly any clear formic acid is dripping over into the collection flask. If one were to swirl the reaction flask, the liquid will appear syrupy and kind of coat the sides of the flask. This is more evident when the flask cools. A quick sniff of the flask may indicate that some formic is still in there, but it should be too minimal to be of any concern. 

Right about now the chemist is probably screaming, "Hey, where the hell is my big yield of you-know-what ". Sorry. Charlie. This way of aminating is easy but chemically it s a crap shoot with yields anywhere from 10-50%. The theoretical odds are against the reaction but if it is done as outlined here, the chances of success are better. Actually, Strike thinks the yields could be higher because half the problem was probably caused by low bromosa-frole yield which we have hopefully corrected in the preceding section ... 

This is the infamous Friedel-Crafts method and works in a manner similar to the previously mentioned method where P2P was made by merging benzene and chloroacetone using AICI3. This method is for speed makers only and is not recommended for conversion of 1,3-benzodioxole. However, this should work in a limited way on catechol. The conversion factor is very low but that isn t a major concern of speed chemists because cheap old benzene is the precursor and all of that benzene that isn t converted can be run back through this simple little process over and over again. Before she knows it, the chemist will have amassed an enormous amount of allylbenzene [139, 140]. 

The way the chemist knows that she has methylamine and not ammonium chloride is that she compares the look of the two types of crystals. Ammonium chloride crystals that come from this reaction are white, tiny and fuzzy. The methylamine hydrochloride crystals are longer, more crystalline in nature and are a lot more sparkly. The chemist leaves the methylamine crystals in the Buchner funnel of the vacuum filtration apparatus and returns the filtrate to the distillation set up so it can be reduced one last time to afford a second crop. The combined methylamine hydrochloride filter cake is washed with a little chloroform, scraped into a beaker of hot ethanol and chilled. The methylamine hydrochloride that recrystallizes in the cold ethanol is vacuum filtered to afford clean, happy product (yield=50%). 

This catalyst should really be purchased rather than made because its use in underground chemistry is limited and is hardly watched at all if not ever. This may change considering its potential as a precursor to the NaBHsCN in Strike s 1 method of choice. There are a lot of ways to make this catalyst, but the least involved is the one using boron trifluoride. What the method calls for is an apparatus called an autoclave. You know how using a vacuum causes the absence of pressure to make things boil at a lower temperature Well, an autoclave is a device that causes an... 

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