Conversion number

Clark, Susan L. and Julian N. Wasserman. The poetics of conversion number symbolism and alchemy in Gottfried s Tristan. Utah studies in literature and linguistics, no. 7. Bern, Las Vegas (NV) Peter Lang, 1977. 

Literature data for the suspension polymerization of styrene was selected for the analysi. The data, shown in Table I, Includes conversion, number and weight average molecular weights and initiator loadings (14). The empirical models selected to describe the rate and the instantaneous properties are summarized in Table II. In every case the models were shown to be adequate within the limits of the reported experimental error. The experimental and calculated Instantaneous values are summarized in Figures (1) and (2). The rate constant for the thermal decomposition of benzoyl peroxide was taken as In kd 36.68 137.48/RT kJ/(gmol) (11). 

In the following, the mass balance for substrate S and hydrogen in the liquid phase are written, considering that assumptions 1 to 4 hold. For a more illustrative view, mass balance is proposed with the concentrations as variables. In general, if the reaction stoichiometry is known, then the conversion number is used as the unified single variable. 

You may encounter questions that ask you to convert between units of measurement in length, weight, or time. To convert from a smaller unit (such as inches) to a larger unit (such as feet), divide the smaller unit by the number of those units necessary to equal the larger unit. To convert from a larger unit to a smaller unit, multiply the larger unit by the conversion number. 

This conversion number, 1.77, had been used in the past because the density of jet fuel is 1.77 pounds per litre. Unfortunately, the number that should have been used to convert litres into kilograms was 0.803. The crew should have added 20 088 L of fuel, not 4916 L. 

The dynamic model developed by Kiparissides et al M,2] and subsequently modified by Chiang and Thompson [ J] can predict the conversion, number of particles, particle diameters, etc., for the continuous emulsion polymerization of vinyl acetate. In this paper, the model is extended to predict molecular weight averages and long chain branching as well. 

Fig. 23A-C. Isobutylene polymerization at — 25 °C. GPC traces of PIBs obtained A as a function of time B initiator ED ratio at the same time C at similar conversion. Numbers at peaks indicate molecular weight distributions of living polymers. H20 C and L/C -ED represent polymers produced by initiation by water, nonliving ionic species, and living complexed species, respectively...

Numbers opposite olefins are percentage olefin conversions, numbers below them are percentage selectivities to stated products. Other products are mainly CO and C02. 

We call a change in the extent of a reaction TZ, A, the conversion of reaction TZ or the conversion according to reaction TZ. Every conversion leads to changes in the amounts of the participating substances, which are proportional to their conversion numbers ... 

Ideally, transport of charge and chemical transformation are closely coupled. By connecting two or more such cells in series, the reactions in the cells are coupled so that they only run forward or backward as a unit. Their drives add up. For simplicity s sake, it is assumed that the reactions are formulated so that the conversion number of electrons is = 1. When the terminals of a ceU in such a series connection are switched, the drive of this cell is given a negative sign— Uke a weight on the opposite side of a scale. 

The generalization on reactions where not all conversion numbers are just +1 (for products) or — 1 (for reactants) is not difficult. Because we would like to retain the usual representation of the conversion formula with the starting substances on the left side of the reaction arrow, we choose the following notation ... 

Because the conversion numbers of reactants are negative, their absolute values characterized by two vertical lines have to be applied. The drive of the process can be calculated by using the same procedure as above ... 

Vc is the sum of the conversion numbers of dissolved substances, more precisely, those substances which show a dependence of the chemical potential upon concentration c this is indicated by the index c. If the chemical potentials of all substances... 

The conversion numbers for the reactants are negative and they are positive for the products. Therefore, the expression in the middle can be read as a difference, which explains the A in the symbol used for the quantity ArV. 

Generalizing this for the case where the conversion numbers are not only +1 or — 1 is just a formality. The energy needed for the general reaction... 

Indifferent Substances The chemical potential of homogeneous mixtures can be applied so that reactions between mixed phases can be treated exactly like reactions between pure substances. As an example the chemical drive Amix for the mixing process of two substances that are indifferent to each other should be determined. Because the conversion numbers va and vb coincide with the mole fractions Xa and Xb, the conversion formula simplifies to... 

The coefficients v represent the conversion numbers. The extent of reaction , can be calculated according to... 

Finally, we will take a brief look at the relation between the order of a reaction and the molecularity mentioned above. Reaction orders are experimentally determined quantities while molecularity (of a reaction step) is a theoretical quantity essential for the elucidation of a reactitMi mechanism. In single-step reactions, molecularity and reaction order (as well as conversion number sum) agree with each other because all the particles react simultaneously with each other according to their appearance in the conversion formula. Conversely, it is not necessarily possible to infer the molecularity of an arbitrary reactimi from its order. This is because in complex reaction processes made up of several single-step reactions, simple rate laws might still be vaUd. 

There is an increase in the concentration of the reaction product that corresponds to the exponential decrease of the reactant concentration. It is equal to the product of the ratio of the conversion numbers and the decrease of concentration (cb,o Cb). Let us consider the reaction... 

Let us return to the simple basic process (a) and generalize it. On the one hand, several electrons will often be exchanged simultaneously and, on the other, several substances can appear in place of the simple substances Rd and Ox. We will indicate the conversion number of the electrons with Ve and allow that Rd and Ox can mean combinations of substances. The generalized process is then ... 

The conversion numbers vg, vbs. .., vd, vds. .. are always negative for reactants and positive for products. In our example on the left they are only —1 or +1, while on the right, they can be random or even fractions. In our example and especially further below, we should note that the more general way of writing on the right. 

The negative drive — can be written as a stun of the potentials of the participating substances, weighted with the conversion numbers [cf. Eq. (4.3)] ... 

The predictive capabilities of the new kinetic model were demonstrated by a direct comparison of model predictions with experimental measurements on monomer conversion, number and weight average molecular weights and molecular weight distribution. The polymerization was carried at different temperatures in a batch, bulk polymerization system. In the temperature range of 100 - 150 °C, a chemical initiator (e.g., Dicumyl Peroxide, DCP) was employed in combination with the thermal initiation of styrene. On the other hand, at higher temperatures (150 - 180 °C), the polymerization was initiated exclusively by the thermal initiation mechanism. 

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