Relative number

Because the digitized areas of the H spectrum give the relative number of pro tons responsible for each signal HETCOR serves as an alternative to DEPT for count mg the number of protons bonded to each carbon... 

Schematic diagram showing the development of a dipolar field and ionization on the surface of a metal filament, (a) As a neutral atom or molecule approaches the surface of the metal, the negative electrons and positive nuclei of the neutral and metal attract each other, causing dipoles to be set up in each, (b) When the neutral particle reaches the surface, it is attracted there by the dipolar field with an energy Q,. (c) If the values of 1 and <() are opposite, an electron can leave the neutral completely and produce an ion on the surface, and the heat of adsorption becomes Q,. Similarly, an ion alighting on the surface can produce a neutral, depending on the values of I and <(), On a hot filament the relative numbers of ions and neutrals that desorb are given by Equation 7.1,which includes the difference, I - <(), and the temperature, T,...

MohsAn early (1822) hardness comparison test involved assigning a relative number to aH known materials (usuaHy minerals and pure metals) by virtue of their relative abHity to scratch one another. The results of this classification are not relatable to other properties of materials or to other measures of hardness. As a result of this limited useflilness, the Mohs hardness test is primarily used for mineral identification. Some examples of the Mohs hardness scale, which ranks materials from 1 to 10, are Hsted in Table 6. 

The relative number of equivalent nuclei associated with each chemical shift is obtained from the integrated spectmm by normalizing the areas so that the area corresponding to the smallest peak in the spectmm is defined as 1. This relation may not be exactly correct in ft experiments where signals may be affected by significant differences in relaxation times for nuclei in different environments. 

The high T] values above conflict with the common behef that distillation is always inherendy inefficient. This behef arises mainly because past distillation practices utilized such high driving forces for pressure drop, tedux ratio, and temperature differentials in teboilets and condensers. A teal example utilizing an ethane—ethylene sphtter follows, in which the relative number for the theoretical work of separation is 1.0, and that for the net work potential used before considering driving forces is 1.4. 

If samples of two metals widr polished faces are placed in contact then it is clear that atomic transport must occur in both directions until finally an alloy can be formed which has a composition showing die relative numbers of gram-atoms in each section. It is vety unlikely that the diffusion coefficients, of A in B and of B in A, will be equal. Therefore there will be formation of an increasingly substantial vacancy concentration in the metal in which diffusion occurs more rapidly. In fact, if chemically inert marker wires were placed at the original interface, they would be found to move progressively in the direction of slowest diffusion widr a parabolic relationship between the displacement distance and time. 

These amounts are in deutsche mark values at the time the original text was written (the late 1980s) and therefore should be used only as relative numbers. 

The relative number of particles backscattered from a target atom into a given solid angle for a given number of incident particles is related to the differential scattering cross section ... 

Fig. 13. The relationship between viscosity and relative number-average molecular weight for a certain resole. Different resoles will have different relationships. Note the non-linearity.

If every collision of a chlorine atom with a butane molecule resulted in hydrogen abstraction, the n-butyl/5ec-butyl radical ratio and, therefore, the 1-chloro/2-chlorobutane ratio, would be given by the relative numbers of hydrogens in the two equivalent methyl groups of CH3CH2CH2CH3 (six) compared with those in the two equivalent methylene groups (four). The product distribution expected on a statistical basis would be 60% 1-chloro-butane and 40% 2-chlorobutane. The experimentally observed product distribution, however, is 28% 1-chlorobutane and 72% 2-chlorobutane. 5ec-Butyl radical is therefore formed in greater anounts, and n-butyl radical in lesser anounts, than expected statistically. 

The primaiy causes of accidents arc mechanical failure, operational failure (human error), miknown or miscclhmcous. process upset, and design error. Figure 14.4.1 is the relative number of accidents that liave occurred in tlie petrochemical field (on a percentage basis), There are lliree steps that normally lead to an accident ... 

Figures 10.29a and b give an indication of the relative numbers of anodes that may be involved for sacrificial anode and impressed-current systems.

Integration (Section 13.10) A technique for measuring the area under an NMR peak to determine the relative number of each kind of proton in a molecule. Integrated peak areas are superimposed over the spectrum as a "stair-step" line, with the height of each step proportional to the area underneath the peak. 

Compounds are formed when atoms of two or more elements combine. In a given compound, the relative numbers of atoms of each kind are definite and constant. In general, these relative numbers can be expressed as integers or simple fractions. 

Strategy Once you deduce the formula of the ionic compound, it s all downhill. Remember, though, that you have to show the relative numbers of cations and anions. 

Formula An expression used to describe the relative numbers of atoms of different elements present in a substance, 34 mass relations in, 69-70q nonmetals, 575q... 

Pure sodium chloride, like pure water, has a definite melting (freezing) temperature (at a given pressure). Separating operations—such as distilling or freezing—do not separate the salt into components. The composition of the salt, whether expressed in relative numbers of sodium and chlorine atoms or in the relative weights of these atoms, is fixed and is represented by the formula NaCl. Sodium chloride, like water, is an example of a pure substance. 

To represent the composition of such a solid, we use the formula NaCl. However, this formula does not indicate that molecules of sodium chloride are present—it is not a molecular formula. It shows the composition by giving the relative number of each kind of atom present and is called an empirical formula. 

The atomic theory provides a ready explanation for the definite composition of chemical compounds. It says that compounds are composed of atoms, and every sample of a given compound must contain the same relative number of atoms of each of its elements. Since the atoms of each element have a characteristic weight, the weight composition of a compound is always the same. Thus, the definite composition of compounds provides experimental support for the atomic theory. 

The empirical formula tells only the relative number of atoms of each element in a molecule. For example, consider ethane. Analysis shows that this is a compound of carbon and hydrogen and that there are three hydrogen atoms for... 

Suppose we burn 46 grams of ethanol. Collection of the products yields 88 grams of carbon dioxide and 54 grams of water. We wish to learn the relative numbers of carbon, hydrogen, and oxygen atoms in the compound, and we can do this by calculating the number of moles of carbon dioxide and water produced by the combustion of the 46 gram sample. Therefore, we calculate ... 

Since the relative number of atoms of each element in the compound is the same as the relative number of moles of atoms of each element in the sample, we can say that the empirical formula of ethanol is... 

Now we know that the relative numbers of atoms in ethanol are two carbon to six hydrogen to one oxygen. We do not know yet whether the molecular formula is C2HsO, CjH 202, C6H 03, or some other multiple of the empirical formula, C2HeO. 

Note In ionic compounds the relative number of positive and negative ions is such that the sum of their electric charges is zero. 

The product yield coefficient can then be calculated, taking into account the relative numbers of carbons in the substrate and product. The molar yield coefficient is then written as... 

This is called Avogadro s theorem (1811) it appears here simply as a definition of molecular weighty and this is really the manner in which the relation is applied in chemistry. The kinetic theory of gases gives a new, and much deeper, significance to the statement by introducing the conception of the molecule this, however, does not concern us in thermodynamics, and since the molecular weights are purely relative numbers, the deductions made in this hook are equally strict whichever standpoint is adopted. 

The solid-state NMR technique may also be used in cellulose derivatives to follow the degree of substitution and degradation of the chain e.g. as found for cellulose nitrate 16). Investigations on the composition of copolymers may also been done as examplared by celluloseacetate-butyrate given in Fig. 6, 20). Here, owing to relaxation differences the spectra cannot be used for elementary analyses, but for estimating the relative number of the components. 

FIGURE B.6 The mass spectrum of neon. The locations of the peaks tell us the relative masses of the atoms, and the intensities tell us the relative numbers of atoms having each mass. 

The empirical formula shows the relative numbers of atoms of each element... 

To convert the mass percentage composition obtained from a combustion analysis into an empirical formula, we must convert the mass percentages of each type of atom into the relative numbers of atoms. The simplest procedure is to imagine that we have a sample of mass 100 g exactly. That way, the mass percentage... 

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