Empirical formula defined

The earlier sections have only considered the way atoms are bonded to each other in a molecule (topology) and how this is translated into a computer-readable form. Chemists define this arrangement of the bonds as the constitution of a molecule. The example in Figure 2-39, Section 2.5.2.1, shows that molecules with a given empirical formula, e.g., C H O, can have several different structures, which are called isomers [lOOj. Isomeric structures can be divided into constitutional isomers and stereoisomers (see Figure 2-67). 

Phosphoric acids and the phosphates maybe defined as derivatives of phosphoms oxides where the phosphoms atom is in the +5 oxidation state. These are compounds formed in the M2O—P20 system, where M represents one cation equivalent, eg, H", Na", 0.5 Ca ", etc. The molecular formula of the phosphoms(V) oxide [1314-56-3] is actually P O q, but this oxide is commonly referred to in terms of its empirical formula, P2O5. StmcturaHy, four phosphoms—oxygen (P—O) linkages are arranged in an approximate tetrahedral configuration about the phosphoms atom in the phosphate anion. Compounds containing discrete, monomeric PO ions are known as orthophosphates or simply as phosphates. 

Compounds that have the empirical formulas MCr02 and DCr204 where M is a monovalent and D a divalent cation, are known as chromites. These are actually mixed oxides and probably are better written as M20-Cr203 and D0-Cr203, respectively. The oxides of D are largely spinels, ie, the oxygen atoms define a close-packed cubic array having the octahedral holes occupied by the Cr(III) cation and the tetrahedral holes occupied by D (54). Chromite ore is an important member of this class of oxides. 

D. consolida, L. From this species Keller isolated three alkaloids of which one (Base A ) was well defined. Markwood obtained three crystalline alkaloids of which delcosine was probably Keller s base A, and Cionga and Iliescu have added to Markwood s observations, but failed to obtain his third base. This work has recently been critically revised by Marion and Edwards, ( > who have isolated from the seeds six alkaloids of which two, delcosine and delsoline, were already known another, consolidine, may be Markwood s third base, and the remaining three are new records for this species, viz. delsonine, lycoctonine and anthranoyllycoctonine. They have also altered the empirical formulas of the alkaloids delcosine and delsoline. 

Cell growth and metabolic activities are similarly described as a simple chemical reaction. It is also necessary to establish a definite formula for dry cell matter. The elemental composition of certain strains of microorganism is defined by an empirical formula CHaO/3Ns. The general biochemical reaction for biomass production is based on consumption of organic substrate, as shown below. Substrate oxidation is simplified in the following biochemical oxidation ... 

We can use Pauling s empirical formula, which defines the Pauling electronegativity scale, for dissociation energies of a diatomic gold molecule. 

Which one of the following could possibly be defined as the ratio of moles of each of the given elements to moles of each of the others (a) Empirical formula, (b) molecular formula, or (c) percent composition by mass. 

An empirical formula, due to Fick, shows that, under simple circumstances where the chemical potential of a component in a system is defined by the equation... 

The nominal mass is defined as the integer mass of the most abundant naturally occurring stable isotope of an element. [3] The nominal mass of an element is often equal to the integer mass of the lowest mass isotope of that element, e.g., for H, C, N, O, S, Si, P, F, Cl, Br, I (Table 3.1). The nominal mass of an ion is the sum of the nominal masses of the elements in its empirical formula. 

Rule 2 Do not define abbreviations for elements (e.g., Fe), empirical formulas (e.g., CH3CH3), units (e.g., mh, g, pm, °C), or a few other commonly used chemical abbreviations (see table A2). (If you are writing for a nonexpert audience, you may want to define even these commonly used terms.)... 

The correlation index, Cl, was originally devised by H. M. Smith from the U.S. Bureau of Mines in 1940 and it relates the average boiling point of a feed to its spe-cihc gravity. It is defined by the following empirical formula ... 

Another parameter that must be taken into account when operating devices in pulsed-power applications is the action, defined as l t, where t is the width of the current pulse. The life (N) of the switch is the number of times the device will deliver power to the load before failure and is also an important parameter used to determine the reliability of the pulse-power system. Switch failure is usually related to mechanical factures caused by thermal stresses due to power dissipation in the device at turn-on. Life is predicted using the empirical formula... 

The molar ratio of the excess amount of Ag+ (defined by AAg) to that of RS ions(defined by ARS) are dose to unity in all the samples, indicating that the side reaction [Eq. (6)] and then its product RSAg should be taken into account to interpret the data of elemental analysis. This RSAg molecular complex was found to be amorphous by XRD observation. It was also found that a particle with a size of 15 nm was almost free from RSAg by comparing the content of empirical formula with that of the theoretical one in Table 4,4.3. The RSAg complex cannot be removed in the present procedure for smaller particles whose size is less than 10 nm due to its small A sp value, but one can eliminate it by a careful control of the pH of suspensions. 

Drop Safety of Bomb Test or Bomb Functioning Test. Drop safety of bomb may be defined as the maximum height of drop for a given bomb oo a given surface without causing the bomb to fail, or without detonation An empirical formula computed at Aberdeen PG before WWII.as a.result of dropping various bombs from an airplane at a height of ca 20 00 ft on 2 ft deep reinforced concrete hard surface laid over a suitable... 

The possibility of predicting thermodynamic properties of redox couples and solutes in different solvents is very important. It should be very useful to develop procedures of transferring thermodynamic data such as redox potentials from solvent to solvent. In fact, the correlation found between kinetic and thermodynamic parameters of reactions in solutions, and solvent parameters such as DN, AN, dielectric constant, etc., indicates that it may be quite feasible to draw empirical formulas which predict, for instance, redox potentials in some solvents, based on well-established data obtained experimentally with other solvents. Thus, it may be possible to define transfer parameters (AG , AH , ASf, etc.) reflecting the difference between aqueous and polar aprotic solutions in the thermodynamic properties of solutes. 

Phosphorus forms two well-defined oxides, namely, diphosphorus trioxide and diphosphorus pentoxide, having the empirical formulas P203 and P205 respectively an intermediate oxide, diphosphorus tetroxide, P204, and possibly the suboxides P40 and P20, are known. 

An extension of isomerism from molecules to ensembles of molecules (EM) leads to new perspectives in chemistry. The left and right hand sides of a stoichiometrically balanced reaction equation are isomeric EM. Any chemical reaction may be regarded as an isomerization, i.e. the conversion of an EM into an isomeric EM. Let A = A1(... A be a finite collection of atoms with the empirical formula A. Any EM that contains each atom of A exactly once is an EM (A). The family of all isomeric EM (A), the FIEM(A) contains the complete chemistry ofA = At,... A . The FIEM(A) is closed and finite. It has well-defined limitations and invariancies. Accordingly, the logical structure of the chemistry of an FIEM(A) is much easier to elucidate than the logical structure of chemistry without the above restrictions [9],... 

Define or identify each of the following molecule, ion, formula unit, formula mass, mole, molecular mass, Avogadro s number, percent, empirical formula, molecular formula, molar mass, empirical formula mass, molecular weight. 

Slight variations in the definition of reaction order may be found in the literature. For example, for some reactions there may be reason to believe that one species (for example, nitrogen) is inert, in the sense that changes in its concentration do not influence the rate of the reaction at constant pressure, and in such cases rij may be defined by considering simultaneous changes in the concentrations of species j and of the inert, with the total pressure held constant. In general, the resulting value of rij diflers from that defined above therefore it is important to ascertain the specific definition employed. An empirical formula that is often useful—for example, in the presence of an inert—is... 

Use Greek prefixes (Table 3.10) to specify the number of atoms of each element in the molecular formula of the compound (di- for two, tri- for three, and so forth). If the compound is a solid without well-defined molecules, name the empirical formula in this way. The prefix for one (mono-) is omitted, except in the case of carbon monoxide. 

While a full-scale field loading test, properly performed and interpreted, will reliably define the foundation soil interaction, such tests are generally not feasible. Thus, the way a soil or rock mass responds to being stressed is usually determined by previous experience in similar conditions, by extrapolating the results of small load tests or by using specific soil properties in various empirical formulae. These soil properties are sometimes inferred from previous experience, but more often reflect the results of laboratory and field tests on soil and rock samples. 

Tonks (T4) has attempted to define the allowable limits of laboratory error in terms of the empirical formula... 

Historically, carbohydrates were defined as substances with the empirical formula Cn(H20)ni. The common sugars such as glucose and fructose (n = m = 6), or sucrose (n=12, m=ll) fit this formula, but nowadays the convention is to regard as a carbohydrate a polyhydroxyaldehyde or polyhydroxy ketone with the classical formula, a molecule closely related to it, or oligomers or polymers of such molecules. Their study evolved as a separate sub-discipline within organic chemistry for practical reasons - they are water-soluble and difficult to crystallise - so that their manipulation demanded different sets of skills from classical natural products such as terpenes, steroids, alkaloids, etc. 

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