/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Problem 97 A reaction of the form $$aA \lon... [FREE SOLUTION] | 91Ó°ÊÓ

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A reaction of the form $$aA \longrightarrow Products$$gives a plot of \(\ln [\mathrm{A}]\) versus time (in seconds), which is a straight line with a slope of \(-7.35 \times 10^{-3} .\) Assuming \([\mathrm{A}]_{0}=\) \(0.0100 M,\) calculate the time (in seconds) required for the reaction to reach \(22.9 \%\) completion.

Short Answer

Expert verified
The time required for the reaction to reach \(22.9\%\) completion is \(36.1 \,\mathrm{s}\).

Step by step solution

01

Calculate the reaction rate constant

The slope of the given plot equals the negative value of the reaction rate constant, so: \[k = -(-7.35 \times 10^{-3})\] \[k = 7.35 \times 10^{-3} \,\mathrm{s^{-1}}\]
02

Determine the concentration of A at 22.9% completion

To find the concentration of A at \(22.9\%\) completion, we'll multiply the initial concentration with the remaining percentage: \[[\mathrm{A}] = [\mathrm{A}]_{0} \times \left(1 - \frac{22.9}{100}\right)\] \[[\mathrm{A}] = 0.0100 \,\mathrm{M} \times \left(1- 0.229\right)\] \[[\mathrm{A}] = 0.0100 \,\mathrm{M} \times 0.771\] \[[\mathrm{A}] = 0.00771 \,\mathrm{M}\]
03

Calculate the time required for 22.9% completion

Now, we can insert the values of \(k, [\mathrm{A}]_{0}\), and \([\mathrm{A}]\) into the formula for the first-order reaction, and solve for the time, \(t\): \[\ln\frac{[\mathrm{A}]_{0}}{[\mathrm{A}]} = kt\] \[\ln\frac{0.0100}{0.00771} = (7.35 \times 10^{-3}) t\] \[0.265 = 7.35 \times 10^{-3}t\] Now we'll solve for \(t\): \[t = \frac{0.265}{7.35 \times 10^{-3}}\] \[t = 36.1 \,\mathrm{s}\] So, it takes 36.1 seconds for the reaction to reach \(22.9\%\) completion.

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Most popular questions from this chapter

The activation energy of a certain uncatalyzed biochemical reaction is \(50.0 \space\mathrm{kJ} / \mathrm{mol} .\) In the presence of a catalyst at \(37^{\circ} \mathrm{C}\) the rate constant for the reaction increases by a factor of \(2.50 \times 10^{3}\) as compared with the uncatalyzed reaction. Assuming the frequency factor \(A\) is the same for both the catalyzed and uncatalyzed reactions, calculate the activation energy for the catalyzed reaction.

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