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Take Home Quiz Show all work! Due Monday 2/26/18 at the start of class. Show all

ID: 711776 • Letter: T

Question

Take Home Quiz Show all work! Due Monday 2/26/18 at the start of class. Show all work! No work no credit!! 1. For the reaction A. Use the table below to determine the rate law, the overall order, value of the rate constant k, and the rate of the fourth experiment and the energy of activation. OH 0,050 0.100 0.050 0.100 CIO 0.020 0.020 0.010 0.035 Te Rate(M/s 1.4 x 10 2.8 x 10 7.0 x 1 25.0 25.0 25.0 25.0 38,0 6.0 x 10 1.4m6", K (002(O 150) Rate Law Order: Energy of Activation B. The following mechanism is proposed: Slow Fast Does the overall reaction and the rate law from the data above? Show reasoning. C. What would happen faster the disappearance of ClO or the appearance of water? Explain why han ClO D. Each elementary step in this mechanism is bimolecular, briefly explain, froma probability standpoint, why a termolecular elementary step is very unlikely the exact Samc ic

Explanation / Answer

1. From the given data for the reaction,

A. from Expt 1 and 3,

[OH-] = constant

when concentration of [ClO2] is halved, rate also halved

order [ClO2] = 1

from Expt 1 and 2,

[ClO2] = constant

when concentration of [OH-] is doubled, rate also doubled

order [OH-] = 2

So,

rate law becomes,

rate = k[ClO2][OH-]^2

k = rate constant

Overall order = 3

Energy of activation (Ea),

ln(k2/k1) = Ea/R[1/T1 - 1/T2]

with,

T1 = 25 oC + 273 = 298 K

T2 = 38 oC + 273 = 311 K

k1 = 1.4 x 10^-3 M/s

k2 = 6.0 x 10^-3 M/s

R = gas constant

So,

ln(6 x 10^-3/1.4 x 10^-3) = Ea/8.314[1/298 - 1/311]

Ea = 86.256 kJ/mol

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B. rate from

step 1: rate = k1[ClO2]^2

which does not match with the rate law found above

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C. Since step 3 is fast, H2O appearence would be faster then ClO2 consumption.

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D. Termolecular mechanism would not justify the mechanism shown above and the reaction rate law would be also incorrect and complicated.