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Backspace End Dehete Summer 2017 Recitation Activity 14 Spring 2018 Key Question

ID: 701754 • Letter: B

Question

Backspace End Dehete Summer 2017 Recitation Activity 14 Spring 2018 Key Questions: 1-4 Consider the reaction: A+2B 2C Trial e/M 2.58x10 2.58 x 10 7.74 x 10 Initial ratea/ M/s 1.26 x 10 2.52 x 10 2.52 x 10 6.47 x 10 2.59 x 10 7.77 x 10 1. How fast is C initially being produced in the first trial? 2. What is the order with respect to [A) -what is the exponent of [A] in the rate law? Explain/ justify your 3. What is the order with respect to [B)-what is the exponent of IB] in the rate law? Explain / justify your reasoning 4. Write the rate law. 5. Calculate the rate constant (k). Include appropriate units.

Explanation / Answer

Ans

Let Rate law

r = k [A]a [B]b

From exp 1 and 2

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

6.47*10^-4/2.59*10^-3 = (1.26/2.52)a

0.25 = 0.5a

0.52 = 0.5a

a = 2

Order with respect to A = 2

From exp 2 and 3

r2/r3 =  [A]2a [B]2b /  [A]3a [B]3b

2.59/7.77 = (2.58/7.74)b

0.33 = 0.33b

b = 1

Order with respect to B = 1

Rate law for this reaction

r = k [A]2 [B]

From exp 1

k = r1/[A]12 [B]1

= (6.47*10^-4) M/s /(1.26*10^-2)2*(2.58*10^-2) M3

= 157.958 M-2 s-1