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A reaction is zero order when the rate of reaction is independent of the concentration of R, often when the catalyst and enzyme are saturated and increasing the concentration of R does not increase the rate. The rate is limited by k only. It can be determined by looking at experimental data. For example, looking at all of your reactants (say, 3), if the concentration of 2 are held constant, while the 3rd is doubled, and the rates of the two trials are the same, then you know that the order of the 3rd reactant is zero since changing its concentration has no effect on the rate of the reactant. If the other two reactants are also zero order, then the overall reaction is zero order since you would total the reactants' orders.
Zero-order reactions are solely k based. the rate=k[A]^0 which makes [A]=1 and therefore rate=k. you can tell if this happens when a graph showing concentration over time is a flat line since this usually happens when an enzyme/catalyst is saturated and the rate is constant. hope this helps
You figure out a reaction is zeroth order the same way you figure out reactions are first or second order. Compare the concentrations given with the changes in initial rate. Rate=k[A]^0 which makes [A]=1 and therefore rate=k.
A zeroth-order reaction has a rate that does not depend on the concentration of any of the reactants but takes place at the same rate no matter the concentration of the reactant. For example, the reaction takes place at the same rate when reactant A's concentration is 1/2 of its initial concentration or 1/4 of its initial concentration or 1/8 of its initial concentration. You can identify a zeroth-order reaction by the graph of the concentration of the reactant against time which gives a straight line with a negative slope which gives the rate of the reaction. The plot of the rate against time is constant with a straight line and a slope of zero.
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