Determine the reaction order What is the value and unit of t

Determine the reaction order.
What is the value and unit of the rate constant for this reaction?

6.5/100 2/28/2018 10:31 AM Print Calculator und Periodic Table Question 21 of 33 Sapling Learning particular reactant decomposes with a half-life of 141 s when its initial concentration is 0.395 M. The same reactant decompo ses with a half-life of 211 s when its initial concentration is 0.264 M Determine the reaction order What is the value and unit of the rate constant for this reaction? Number Select answer

Solution

We know that the half life of a reaction is inversely proportional to (initial concentration)^1-n where n is the order of reaction.

thus t1/t2 = [a1/a2]^1-n

Substituting the given values

141/211 = [0.395/0.264]^1-n

and solving for n , we get n = 2

Thus the order of the reaction is 2.

For a second order reaction, half life t = 1/ka

given t =141s and a = 0.395M

So k = 1/ 0.395M x 141s

=0.01795 M^-1s^-1