Reaction rates dependence on concentration

Taylor series as functions of experimental conditions. This is exactly analogous to the analysis of In r described previously except that, by means of a tentative model, the primary reaction rate dependence on concentrations, temperature, and other experimental factors has been eliminated. This permits the rate equations to be Integrated approximately correctly. 

When some CaCOs first reacts with H30", the rate of the forward reaction is large. The rate of the reverse reaction is zero until some products form. As the reaction proceeds, the forward reaction rate slows as the reactant concentrations decrease. At the same time, the reverse rate increases as more products of the forward reaction form. When the two rates become equal, the reaction reaches chemical equilibrium. Because reaction rates depend on concentrations, there is a mathematical relationship between product and reactant concentrations at equilibrium. For the reaction of limestone and acidified water, the relationship is... 

Rate laws, which are used to suggest mechanisms, are determined by studying how reaction rate depends on concentration. 

Explain why reaction rate depends on concentration, physical state, and temperature ( 16.1) (EPs 16.1-16.6)... 

Molecules must collide in order to react used to account for the fact that reaction rate depends on concentrations of reactants and temperature... 

Why does equilibrium occur We saw in Chapter 12 that molecules react by colliding with one another, and the more collisions, the faster the reaction. This is why reaction rates depend on concentrations. In this case the concentrations of FI2O and CO are lowered by the forward reaction ... 

Reaction rates depend on concentrations of reactants that change during the reaction. Thus, the rate of a reaction will usually be greatest at the beginning of a reaction and will decrease with time until equilibrium is established. One common type of chemical reaction is the first-order reaction, in which the rate of disappearance of a reactant is proportional to the reactant concentration. This leads to an exponentially decreasing reaction rate as time proceeds (see Section 4.3). Other types of kinetics are also possible. 

The reaction rate depends on concentration, pressure, and temperature of the reactants and products of the reaction. It is an intensive property because it has specific units and applies for any closed or open system. Since the concentration varies with time in a batch system or with position in a continuous system, the reaction rate also depends on these variables. This rate decreases with time or position, and tends to zero when all the reactant is consumed or in the equilibrium. The rate of the reaction is defined as a function of a component, and for a reversible reaction of the type aA + bB- rR + sS, the resulting reaction rate is expressed as follows ... 

Rate Laws How the Reaction Rate Depends on Concentration... 

For application in chemical sensors, two aspects of chemical kinetics are important. The first is If the reaction rate depends on concentration, then it should be possible to determine concentration values by measuring reaction rates. The second aspect is If the amount of a catalyst affects the reaction rate, then in some cases it should be possible to determine catalyst concentrations by kinetic measurements. 

The rate of a reaction is a measure of the amount of product that is formed per unit of time. The preceding equations show that the rate is the product of the rate constant and the reactant concentration(s), so reaction rates depend on concentration, whereas rate constants are independent of concentration. Therefore, when we cointare two reactions to see which one occurs more readily, we must compare their rate constants and not their concentration-dependent rates of reaction. (How rate constants are determined is explained in Appendix n.)... 

Table 6.8 reports the relative reaction rates of Diels-Alder reactions of 2,5-dimethylbenzoquinone with tran -piperylene in different lithium salt solutions. The data show that the reaction rate depends on the concentration of LT and that in 4.0m LT-AC and 4.0m LT-DE the rate accelerations are comparable to that exhibited in 5.0m LP-DE and 5.0m LP-AC. 

In the usual case, t and will be known. Equation (1.49) is an algebraic equation that can be solved for If the reaction rate depends on the concentration... 

This result assumes constant density and is most useful when the reaction rate depends on a single concentration, SS-a = A(ciout)-... 

At the platinum electrode the individual steps of the four-electron reaction cannot be studied separately. Slope b has its usual value of about 0.12 V, but in contrast to what is seen at the mercury electrode, the polarization is practically independent of solution pH (i.e., the potential at a given current density shifts by 0.06 V in the negative direction when the pH is raised by a unit). It follows that the reaction rate depends on hydrogen ion concentration. The step in which an electron and a proton are transferred while the 0-0 bond is broken is probably the ratedetermining step. 

The order of the reaction is 2 + 1 = 3, whereas the molecularity of the reaction, as given by the equation is 4. This reaction can be treated as a representative example which shows that the order of a reaction is strictly an experimental quantity, being concerned solely with the manner in which the rate depends on concentration. In other words, the order of a reaction should be regarded as a mathematical convenience and not as a fundamental property of the reaction. It must be mentioned here that the order of a reaction corresponds to the... 

Operation with an excess of ammonia in the reactor has the effect of increasing the rate due to the C fHl term. However, operation with excess ammonia decreases the concentration of ethylene oxide, and the effect is to decrease the rate due to the CEO term. Whether the overall effect is a slight increase or decrease in reaction rate depends on the relative magnitude of a and b. Consider now the rate equations for the by product reactions ... 

The orders of each reactant are empirically determined values. They provide us with a way to describe the effect of concentration of each species on the overall rate. In simple reactions, orders are zero or integer values, ranging from one to three, though they can be non-integer values. The higher the order for any one species, the more the reaction rate depends on the concentration of this species. The rate constant is also an empirically determined value that provides us information about how easily a reaction occurs. 

The results show that the technetium complexes are more labile than the rhenium complexes. The overall reaction rate depended on the concentrations of both hexachlororhenate and hydrogen ion, but was independent of the chloride concentration. 

No evidence of ruthenium metal formation was found in catalytic reactions until temperatures above about 265°C (at 340 atm) were reached. The presence of Ru metal in such runs could be easily characterized by its visual appearance on glass liners and by the formation of hydrocarbon products (J/1J) The actual catalyst involved in methyl and glycol acetate formation is therefore almost certainly a soluble ruthenium species. In addition, the observation of predominantly a mononuclear complex under reaction conditions in combination with a first-order reaction rate dependence on ruthenium concentration (e.g., see reactions 1 and 3 in Table I) strongly suggests that the catalytically active species is mononuclear. 

Rate of reaction usually depends on concentration of reactants (and sometimes of products), and usually increases as concentration of reactants increases. Thus, many combustion reactions occur faster in pure oxygen than in air at the same total pressure. 

In this case, the actual redox step is preceded by the formation of an adduct or a complex between the catalyst, the substrate and dioxygen. The order of these reaction steps is irrelevant as long as the rate determining step is Eq. (8). If Eqs. (6) and (7) are rapidly established pre-equilibria the reaction rate depends on the concentrations of all reactants. In some instances, the rate determining step is the formation of the MS complex and the reaction rate is independent of the concentration of dioxygen. 

Background Reaction rates depend on several criteria the concentration of the reactants, the nature of the reaction, temperature, and presence of catalysts. The rate of most reactions increases when the concentration of any reactant increases. For the reaction... 

Once the values of a, ft, etc., are determined experimentally, the rate law is defined. In reality, reaction order provides only information about the manner in which rate depends on concentration. 

Micellar catalytic methods were used to operate a choice between these two mechanisms. When an ion-radical has a charge opposite to that of the micelle surface, it is trapped by the micelle (Okamoto et al. 2001). In the presence of a surface-active compound, the aromatic substrate is nitrated in the very depth of a micelle, and the reaction rate depends on the local concentration of the nitrating agent on phase boundaries between the micelle and solution. A positively charged... 

In nature, the reaction rate depends on the reactant concentration. However, practically speaking, when a reactant exists at a very high concentration, it is essentially unchanged due to the reaction, and the reaction is called pseudo-zero order. 

The reaction rate law is an empirical relation on how the reaction rate depends on the various species concentrations. For example, for the following reaction. 

For an unknown reaction, the reaction law cannot be written down simply by looking at the reaction equation. Instead, experimental study must be carried out on how the reaction rate depends on the concentration of each species. For elementary reactions, the reaction rate follows the law of mass action and can be written by looking at the reaction. If the following reaction is an elementary reaction... 

Generally the reaction rate depends on the concentration in a non-linear fashion. The change in concentration divided by the contact time or some other rubbish is not a measure of the reaction rate. 

---