# 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...

Take...

([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 trials...sa trial 1

and solve for k....

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