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The half-life of a reaction, t 1/2, is the time it takes for the reactant concen

ID: 1002922 • Letter: T

Question

The half-life of a reaction, t1/2, is the time it takes for the reactant concentration [A] to decrease by half. For example, after one half-life the concentration falls from the initial concentration [A]0 to [A]0/2, after a second half-life to [A]0/4, after a third half-life to [A]0/8, and so on. on.

For a first-order reaction, the half-life is constant. It depends only on the rate constant k and not on the reactant concentration. It is expressed as

t1/2=0.693k

For a second-order reaction, the half-life depends on the rate constant and the concentration of the reactant and so is expressed as

t1/2=1k[A]0

What would be the initial rate in an experiment with initial concentrations [ (CH3) 3N]=4.2×102M and [ClO2]=3.4×102M?

Explanation / Answer

The half-life of a reaction, t1/2, is the time it takes for the reactant concentration [A] to decrease by half. For example, after one half-life the concentration falls from the initial concentration [A]0 to [A]0/2, after a second half-life to [A]0/4, after a third half-life to [A]0/8, and so on. on.

For a first-order reaction, the half-life is constant. It depends only on the rate constant k and not on the reactant concentration. It is expressed as

t1/2=0.693k      

Half life does not depends up on initial concentration of reactants . so it is first order reaction

Rate law

Rate = K [(CH3)3N][Clo2]

          K*4.2*10-2 * 3.4*10-2