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Specific Rate Constant

Evaluate the specific rate constant for the reaction at the temperature for which the data were obtained. The rate-law expression is rate=k[A][B]squared.

A + B>>>>>> C

Experiment Initial [A] Initial [B] Initial Rate of Formation of C
1 0.10 M 0.10 M 4.0 X .00010 M/min
2 0.20 M 0.20 M 3.2 X .0010 M/min
3 0.10 M 0.20 M 1.6 X .0010 M/min

Solution This solution is FREE courtesy of BrainMass!

You need to isolate the variables in this type of question...just follow the general technique...

Write the general rate law for the reaction

Rate = k[A]^a[B]^b

where a and b are exponents of [A] and [B] respectively...

Then to find a we choose two trials where the concentration of A changes, but B does not, so we can find the effect that A has on the rate.

Looks like trials 2 and 3...

([A2]/[A3])^a = R2/R3

where a is the exponent...

(0.20/0.10)^a = 3.2/1.6

2^a = 2

a = 1

Now do the same for B

Trials 3 and 1

([B3]/[B1])^b = R3/R1

b = 2

Now the rate law is as you found it.....
rate = k[A][B]^2

plug in any one of the trial 1

4.0 X .00010 = k[0.1][0.1]^2

and solve for k....