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You and your lab partner are studying the rate of a reaction, A + B --> C. You m

ID: 1024016 • Letter: Y

Question

You and your lab partner are studying the rate of a reaction, A + B --> C. You make measurements of the initial rate under the following conditions:

(a) Which of the following reactant concentrations could you use for experiment 3 in order to determine the rate law, assuming that the rate law is of the form, Rate = k [A]x [B]y? Choose all correct possibilities.

[A] = 0.5 and [B] = 3.6

[A] = 0.5 and [B] = 5.4

[A] = 1.0 and [B] = 5.4

[A] = 2.0 and [B] = 1.8

[A] = 1.0 and [B] = 1.8

[A] = 1.0 and [B] = 3.6

[A] = 1.5 and [B] = 1.8

[A] = 2.5 and [B] = 1.8

(b) For a reaction of the form, A + B + C --> Products, the following observations are made: doubling the concentration of A increases the rate by a factor of 2, doubling the concentration of B has no effect on the rate, and doubling the concentration of C increases the rate by a factor of 8. Select the correct rate law for this reaction from the choices below.

Rate = k[A][B][C]

Rate = k[A][C]    

Rate = k[A]2 [C]

Rate = k[A][C]2

Rate = k[A]2 [C]2

Rate = k[A]3 [C]

Rate = k[A][C]3

(c) By what factor will the rate of the reaction described in part (b) above change if the concentrations of A, B, and C are all halved (reduced by a factor of 2)? The rate will be the original rate multiplied by a factor of _____ .

experiment [A] Molarity [B] Molarity 1 0.5 1.8 2 1.0 1.8

Explanation / Answer

Doubling the concentration of A increases the rate by a factor of 2,So A power is one. Doubling the concentration of B has no effect on the rate,the power of B is zero and doubling the concentration of C increases the rate by a factor of 8. The power of C is 3

B. Rate = k[A][C]3

C. Rate = k[A][C]3

    Rate = k[A][C]3

            = K1/2[A] *(1/2)3 [C]3

            = K[A][C]3 /16

16* Rate = K[A][C]3

16 time