Relationship between reaction time and

Fig. 5.1 Relationship between reaction time and temperature for a chemical reaction.

The results from Basic Protocol 1 are expected to be consistent with traditional initial velocity assumptions for enzyme kinetics (unit cl /). The assay, as presented, includes four time points (along with a zero-time value) in order to establish the relationship between reaction time and product formed. Representative data, demonstrating the hyperbolic nature of this relationship, are presented in Figure C1.2.3. In this case, only the initial time points at the lowest enzyme concentration are consistent with the linear initial velocity assumption. If... 

Develop a batch-reactor design equation from the mass balance. To find the required holding time, a relationship between reaction time and the rate of conversion of acetylene must be developed. This may be developed from a mass balance on the batch reactor. Since the molar density of the reacting mixture is not constant (there is a net change in the number of moles due to reaction), the pressure of the reactor will have to change accordingly. 

Fig. 5 Relationship Between Reaction Time and Glass Transition Temperature (Tg) of Polyester Mixture from Water-Precipitated, Hexanoylated Steam Exploded Fibers.

Table 2.1 summarizes the observation results revealing the relationship between reaction time and morphological transition at different temperatures. 

The effect of ionic liquid as solvent on the radical graft polymerization of MMA initiated by CB-Azo was investigated. Figure 9 shows the relationship between reaction time and conversion in ionic liquid and 1,4-dioxane. It was found that the rate of the polymerization in ionic liquid was considerably larger than that in 1,4-dioxane. 

As discussed in section 2.7, film thickness is dependent on grafting density. Ellipsometry results demonstrated a relationship between film thickness and reaction time (Tables 5.3-1, 5.3-2). It is suspected that these results demonstrate a relationship between reaction time and grafting density. 

Inferring What relationship exists between reaction time and reaction rate ... 

Table 7.2 Relationship between relaxation time and rate constant for some simple reactions...

Since MeOH or MeOAc carbonylation is generally a very selective reaction, the reactor composition at any time throughout the reaction can be calculated from the amount of CO consumed. From these measurements the relationship between reaction rate and reactor composition can be established. By obtaining IR data at the same time, the nature and amount of catalyst species present can be measured to relate to rate and reaction composition. At the same time, useful data about the water gas shift reaction can be obtained from the increase in the CO2 peak. 

TABLE III. RELATIONSHIP BETWEEN REACTION TIME, TEMPERATURE, REACTION SEVERITY AND CONVERSION OF WYODAK COAL TO PYRIDINE SOLUBLES... 

In kinetic studies it is not necessary to use rates for determination of the rate parameters. In eqs 2-4 r represents the rate expression for the reaction under consideration, whatever its mathematical form. This can be inserted in eq 2, and subsequently integrated after separation of variables, leading to eq 5. The result may be an implicit expression, containing the rate parameters, describing the relationship between space-time and conversion. It will be shown later that this relationship can also be used for parameter determination. 

Rate constant the proportionality constant in the relationship between reaction rate and reactant concentrations. (15.2) Rate of decay the change in the number of radioactive nuclides in a sample per unit time. (21.2)... 

The general relationship between reaction time t and rate — rA at constant volume is [41,42]... 

When setting up methods of enzyme assay, it is necessary to (1) explore the relationship between reaction velocity and substrate concentration over a wide range, (2) determine K and (3) detect any inhibition at high substrate concentrations. Zero-order kinetics are maintained if the substrate is present in large excess (i.e., concentrations at least 10 and preferably 100 times that of the value of K ,). When [S] = 10 X K V is approximately 91% of the theoretical y,nax. The K , values for the majority of enzymes are of the order of 10 to 10" mol/L therefore substrate concentrations are usually chosen to be in tlie range of 0.001 to O.lOmol/L. On occasion, the optimal concentrations of substrate cannot be used (e.g., when the substrate has limited solubility or when the concentration of a given substrate inhibits the activity of another enzyme needed in a coupled reaction system). 

Overview. In Chapter 2, we showed that if we had the rate of reaction as a function of conversion, = /(X), we could calculate reactor volumes necessary to achieve a specified conversion for flow systems and the time to achieve a given conversion in a batch system. Unfortunately, one is seldom, if ever, given = yiX) directly from raw data. Not to fear, in this chapter we will show how to obtain the rate of reaction as a function of conversion. This relationship between reaction rate and conversion will be obtained in two steps. In Step 1, Part 1 of this chapter, we define the rate law, which relates the rate of reaction to the concentrations of the reacting species and to temperature. In Step 2, Part 2 of this chapter, we define concentrations for fiow and batch systems and develop a stoichiometric table so that one can write concentrations as a function of conversion. Combining Steps 1 and 2, we see that one can then write the rate as a function conversion and use the techniques in Chapter 2 to design reaction systems. 

FIGURE 25.2 The Arrhenius equation relationship between reaction temperature and time. 

When the enzyme is saturated with respect to substrate, then the overall reaction is first order with respect to enzyme concentration (fc[S] = constant in Equation 22.13). This becomes the basis for enzyme determination since a linear relationship between reaction rate and enzyme concentration will exist. Since substrate is consumed in the reaction, however, it must be kept at a high enough concentration that the reaction remains zero order with respect to substrate during the time of the reaction (i.e., the enzyme remains saturated). Eventually, at high enzyme concentrations, insufficient spbstrate will be available for saturation, and a plot similar to Figure 22.2 will result. 

The First Quantitative Model followed the introduction of mathematics into the study of chemical kinetics. This made it possible to establish the first proportionality relationships between reaction rate and the number of particles reacting in a given time. 

For spectrophotometric detection, Figure 10.1 illustrates the relationship between these times and the predicted absorbance at true zero time, and the initial absorbance at the start of the detection system. The reaction has a pseudo-first-order rate constant = k,[R], so that the time dependence of the absorbance change is given by... 

The Decreasing Model (DM) This model is mainly based on the idea that a slow reaction takes a long time and a fast reaction takes a short time or reaction rate is inversely proportional to time . The subjects have a general picture of how different reactions tend to occur, however they cannot/did not explain how reaction rate changes as a reaction progresses. While the relationship between reaction rate and time was graphically illustrated in a scientific way, the students interpretations and rationale were different from the established chemical perspective. In the transcript below, R and S stand for the researcher and the student respectively. 

Two separate samples of NasCgo were prepared by direct reaction of Ceo with sodium metal vapor, and subjected to different annealing times of 10 16 days. C and Na solid-state NMR, along with elemental analysis, powder XRD and Raman spectroscopy, were used to characterise both samples. Na and C solid-state NMR spectra of the two samples are significantly different, suggesting a relationship between annealing times and the final structure of the alkali fulleride. Na VTMAS NMR experiments reveal the existence of two or three distinct Na species and reversible temperature-dependent diffusion of sodium ions between octahedral and tetrahedral interstitial sites. C MAS NMR experiments are used to identify resonances corresponding to free Ceo and fulleride species. ... 

The number of alternative stimuli plus the number of alternative responses and the reaction times are strongly related. But the exact relation is questionable. The law of Hick postulates a logarithmic fit and has dominated the discussion. The question arises whether new data fit Hick s law or some other law. Five subjects with nearly 10,000 measurements were used to answer this question. A linear relation was found between reaction time and the number of alternatives when the number of alternatives is not too high. With more alternatives, the relationship is clearly non-linear. 

The reaction tasks of schizophrenics are altered in some characteristic ways. There is a long known increase of reaction time (eg Maier et al. 1994, Carnahan et al. 1997) and effects like inhibition of return (eg Huey et al. 1994), the modality shift effect (Hanewinkel et al. 1996, Maier et al. 1994, Ferstl et al. 1994) and the crossover effect (Maier et al. 1994). Some authors have examined the relationship between reaction tasks and evoked potentials (Salisbury et al. 1994a, Salisbury et al. 1994b, Strandburg et al. 1994), some the saccadic reaction time (Belin et al. 1995). 

This first hypothetical relationship between reaction time data and ERP data shall be explained by examples. 

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