A Qualitative Measurements

Note It is convenient to work in pairs for this experiment. 

Preparation Sign in at www.cengage.com/logln to answer Pre-Lab Exercises, access videos, and read the MSDSs for the chemicals used or produced in this procedure. Review Section 2.5. 

Apparatus A 1-L beaker, three calibrated Pasteur pipets, six 13-mm x 100-mm test tubes, and flameless heating. 

Setting Up As accurately as possible, calibrate several Pasteur pipets to contain 1.5 mL. In separate labeled test tubes, place 1.5 mL of a 0.2 M stock solution of each of fhe following substrates in 15 M(90%) acetic acid (a) phenol, (b) anisole, (c) diphenyl ether, (d) acetanilide, (e) 4-bromophenol, and (f) 1-naphthol. Use special care to ensure that one stock solution is not contaminated by another during any transfer operations you perform. 

Use fhe 1-L beaker to make a water bath and establish a bath temperature of 35 2 °C. Suspend the test tubes partially in the water bath by looping a piece of copper wire around the neck of the test tube and over the rim of the beaker. Transfer abouf 25 mL of a solution containing 0.05 A4 bromine in 15 M acetic acid to an Erlenmeyer flask, and equilibrate this solution in the water bath for a few minutes. 

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Provides a qualitative measure of risk Provides a coarse quantitative measure of risk Provides an absolute quantifalnc measure of risk... 

The other detonability length scale is the detonation cell width, X (also called cell size) which is the transverse dimension of diamond shaped cells generated by the transverse wave stmctnre at a detonation front. It has a fish scale pattern (see Figure 4-4). Detonation cell widths are nsnally measured by the traces (soot) deposited on smoke foils inserted in test vessels or piping surfaces. The more reactive the gas-air mixture, the smaller is the cell size. The same is tme for chemical indnction length as a qualitative measure of detonability. The cell width, X, is a parameter that is of practical importance. The transition from dehagration to detonation, propagation, and transmission of a detonation, can to some extent be eval-... 

In order to obtain information as to the extent to which the bond strength S of an orbital can be considered a qualitative measure of its bondforming power and also as to the quantitative relation between the energy of a bond and the strengths of the bond orbitals involved in its formation, we have now carried out the thorough discussion of various sp and spd one-electron bonds between identical atoms. 

A qualitative measure of the corrosion rate can be obtained from the slope of the curves in Fig. 2. Z INT is given in units of s ohm" . Owing to the presence of the uncompensated ohmic resistance and lack of values for Tafel slopes [Eq. (2)], data in Fig. 2 should be viewed as indicative of significant changes in corrosion rates. Corrosion loss remained low during the first 2 months, followed by a large increase for both flushed samples and controls. The corrosion rate increased when the surface pH reached values of 1 or less. Total corrosion loss as determined from integrated Rp data was less for the control than for the flushed sample. 

Lazarsfeld, P. F., Barton, H. A. Qualitative measurement in the social sciences classifications, typologies, and indices. In The Policy Sciences, Lemer, D., Lasswell, H. D. (eds.), Stanford University Press, Stanford, CA, 1951, pp. 151-192. 

It is possible to extend the line scanning method to two-dimensional scanning. In its simplest form, the display is made bright every time an X-ray photon is counted, thus generating a image of bright dots. The dot density provides a qualitative measure of the concentration of the element of interest. 

For semicrystalline isotropic materials a qualitative measure of crystallinity is directly obtained from the respective WAXS curve. Figure 8.2 demonstrates the phenomenon for polyethylene terephthalate) (PET). The curve in bold, solid line shows a WAXS curve with many reflections. The material is a PET with high crystallinity. The thin solid line at the bottom shows a compressed image of the corresponding scattering curve from a completely amorphous sample. Compared to the semicrystalline material it only shows two very broad peaks - the so-called first and second order of the amorphous halo. 

Proton NMR has the advantage of relative experimental ease due mainly to its intrinsic high sensitivity, though the relaxation properties of the proton resonances are generally more difficult to interpret in terms of dynamics than are those from protonated carbon nuclei. The widths of the proton resonances can conveniently be used as a qualitative measure of some of the motional properties. 

From knowledge presently available, the ability of PAH to bind covalently to cellular macromolecules appears to depend mainly on two factors the ease of formation of PAH radical cations, which is measured by their IP, and localization of positive charge in the radical cation. The IP of numerous PAH have been determined and compared to a qualitative measure of their carcinogenicity (16). 

There are many ways of expressing the relative amounts of solute(s) and solvent in a particular solution. The terms saturated, unsaturated, and supersaturated discussed above give a qualitative measure of solubility, as do the terms dilute and concentrated. Dilute refers to a solution that has a relatively small amount of solute in comparison to the amount of solvent. Concentrated refers to a solution that has a relatively large amount of solute in comparison to the solvent. These terms are very subjective and chemists prefer to use quantitative... 

The chemical shift dispersion (Table 1) and the temperature dependence of the resonance hne shape provides a qualitative measure of whether the structure is well ordered [2]. However, NMR spectroscopy also provides information relevant to the problem of protein folding in the study of the molten globule states. NMR spectroscopic investigations of molten globules may be more demanding than those of ordered proteins due to spectral overlap arising from poor shift dispersion and to short relaxation times that are due to conformational exchange at intermediate rates on the NMR time scale. 

It has been shown that radio frequency impedance (RFI) is an effective tool for moifitoring cell density and cell growth of bioprocesses. The fermentation process, quite complex, is oftentimes difficult to sample and monitor. The RFI measurement could detect cell viability of Escherichia coli during the fermentation, serving as a qualitative measure of the metabolic load of the cell, and thus provide an in situ indicator of the optimal harvesting times. 

In an attempt to find an in vitro assay to predict differences in the neurotoxic potential of bisindole alkaloids, an assay using cultured rat midbrain cells was developed. This system provided a qualitative measure of the effect of compounds on neuronal tissue, and when several compounds (for which clinical toxicity data were available) were evaluated using this method the results were consistent in rank order with the compounds clinical manifestation of neurotoxicity. When vinepidine was studied in this system, it was found to produce a minimal effect (Fig. 7). 

A novel method for estimating ring current in aromatic molecules has recently been provided (79TL437). This involves measurement of the H NMR a- and y-methyl chemical shifts in compounds (258), readily prepared from ArNth and 2,4,6-trimethyIpyrylium perchlorate. Quantity D defined by equation (18) is a qualitative measure of ring current... 

The change of the fluorescence maximum with the excitation wavelength gives a qualitative measure of the polydispersity (33,34). 

Helicity is defined as a qualitative measurement of how a topological configuration is linked, knotted, or twisted. If A is the vector potential of electromagnetism, the quantity then defines magnetic helicity. In order to obtain a nonnull value for K, the condition A (V A) /- 0 must be verified in the volume... 

This activity is a qualitative measure of the specific heat of two common kitchen ingredients rice and salt. 

This expression is by the factor (rf/i/rf) smaller than the one originally given by Peterlin (76). However, since the coil expansion is a qualitative measure of the state of deformation of coil molecules in laminar shear flow and, moreover, the first relaxation time is, in general, by far the largest one, the original equation of Peterlin can be used unchanged, if desired. 

If multiple procedures are performed, a qualitative measure of time dependence can be gained. This is achieved by linking two ramps in an up-and-down sequence and examining the area of hysteresis. A second option is to connect three segments as an up ramp, a peak hold step, and a down ramp sequence this option has the effect of altering the area of hysteresis because the sample is broken down more effectively before the down step. 

A comparison of the 13C NMR chemical shift of the para carbon in vinyl cations 389a and 390 and the sp2 hybridized l-(p-tolyl)ethyl cations with an additional 1-cyclopropyl- (391) or 1-methyl substituent (392) (Figure 14)150151 gjVes a qualitative measure of the electron demand of various 1-p-tolyl- substituted sp2- and sp-hybridized carbocations. 

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