Not understanding how I\'m getting the rate law expression wrong?? Please help :

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Not understanding how I'm getting the rate law expression wrong??

Please help :(

The following data were obtained for the reaction 2 CIO2(aq) + 2 OH-(aq) CO-Taq) + CIO2Taq) H20(1) where the rate is the following dICio2]l Rate =-at- dt [CIO2lo [OH lo Initial Rate (mol/L) (mol/L) 0.0570 0.114 0.114 0.114 mol L-1 -1 6.56×10-2 2.62x10-1 1.31×10-1 0.114 0.0570 (a) Determine the rate law and the value of the rate constant. (Rate expressions take the general form: rate = k· [A]·[B]b.) rate law: chemPad Help Greek rate k [CLO21 OH11 rate-k* [CLO 21*2[OHA-11 Remember that answers are case- sensitive. Your answer contains an incorrect or incomplete chemical formula. The equation described in your answer is not balanced rate constant 177.1125 L2 moi-2 s-1

Explanation / Answer

In order to calculate the rate law expression for a A+B reaction, we need to apply Initial Rates Method.

Note that the generic formula goes as follows:

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

Note that if we got at least 3 sets of point, in which we have A and B constant, then we could use:

r1 / r2 = (k1 [A]1^a [B]1^b) / (k2 [A]2^a [B]2^b)

If we assume K1 and K2 are constant, then K1= K2 cancel each other

r1 / r2 = ([A]1^a [B]1^b) / ( [A]2^a [B]2^b)

Then, order according to [A] and [B]

r1 / r2 = ([A]1/[A2])^a * ([B]1/[B]2)^b

If we get two points in which A1 = A2, then we could get B, and vise versa for A...

From the data shown in YOUR table

from point 1 and 2, OH cnacels

(6.56*10^-2)/(2.62*10^-1) = (0.057)/(0.114))â

0.25 = 0.5 ^ClO2

ClO2 = ln(0.25)/(ln(0.5) = 2

2nd order with respect to ClO2

now, choose points 2 and 3

(2.62*10^-1)/(1.31*10^-1) = (0.114/0.057) ^b

b = 1

then

Rate = k*[ClO2]^2 * [OH-]

answers are case sensitive, so avoid CLO2, use ClO2-

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