/*! 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 81 The activation energy of an unca... [FREE SOLUTION] | 91Ó°ÊÓ

91Ó°ÊÓ

The activation energy of an uncatalyzed reaction is \(95 \mathrm{~kJ} / \mathrm{mol}\). The addition of a catalyst lowers the activation energy to \(55 \mathrm{~kJ} / \mathrm{mol}\). Assuming that the collision factor remains the same, by what factor will the catalyst increase the rate of the reaction at (a) \(25^{\circ} \mathrm{C}\), (b) \(125^{\circ} \mathrm{C}\) ?

Short Answer

Expert verified
At 25°C (298.15 K), the catalyst increases the rate of the reaction by a factor of approximately 9.82. At 125°C (398.15 K), the catalyst increases the rate of the reaction by a factor of approximately 20.64.

Step by step solution

01

Convert temperatures to Kelvin

First, we need to convert the given temperatures 25°C and 125°C to Kelvin. To convert Celsius to Kelvin, use this equation: Temperature(K) = Temperature(°C) + 273.15 T1 = 25 + 273.15 = 298.15 K T2 = 125 + 273.15 = 398.15 K
02

Set up the Arrhenius equation ratio for each temperature

Let's set up the ratio of the rate constants with the catalyst (kc) to without the catalyst (ku) for each temperature: T1: \(\frac{k_{c1}}{k_{u1}} = \frac{Ae^{\frac{-55}{8.314\times 298.15}}}{Ae^{\frac{-95}{8.314\times 298.15}}}\) T2: \(\frac{k_{c2}}{k_{u2}} = \frac{Ae^{\frac{-55}{8.314\times 398.15}}}{Ae^{\frac{-95}{8.314\times 398.15}}}\)
03

Solve for the ratio of rate constants

We can cancel the collision factor A since it remains the same for both reactions. This leaves us with equations involving only the activation energies and temperatures: T1: \(\frac{k_{c1}}{k_{u1}} = \frac{e^{\frac{-55}{8.314\times 298.15}}}{e^{\frac{-95}{8.314\times 298.15}}}\) T2: \(\frac{k_{c2}}{k_{u2}} = \frac{e^{\frac{-55}{8.314\times 398.15}}}{e^{\frac{-95}{8.314\times 398.15}}}\) Now we can solve for the fractions: T1: \(\frac{k_{c1}}{k_{u1}}\approx 9.82\) T2: \(\frac{k_{c2}}{k_{u2}}\approx 20.64\) These values tell us how much faster the reaction is with the catalyst compared to without. At 25°C (298.15 K), the catalyst increases the rate of the reaction by a factor of approximately 9.82. At 125°C (398.15 K), the catalyst increases the rate of the reaction by a factor of approximately 20.64.

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Over 30 million students worldwide already upgrade their learning with 91Ó°ÊÓ!

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

The reaction \(2 \mathrm{NO}_{2} \longrightarrow 2 \mathrm{NO}+\mathrm{O}_{2}\) has the rate constant \(k=0.63 \mathrm{M}^{-1} \mathrm{~s}^{-1}\). Based on the units for \(k\), is the reaction first or second order in \(\mathrm{NO}_{2} ?\) If the initial concentration of \(\mathrm{NO}_{2}\) is \(0.100 \mathrm{M}\), how would you determine how long it would take for the concentration to decrease to \(0.025 \mathrm{M} ?\)

The rate of the reaction \(\mathrm{CH}_{3} \mathrm{COOC}_{2} \mathrm{H}_{5}(a q)+\mathrm{OH}^{-}(a q) \longrightarrow\) \(\mathrm{CH}_{3} \mathrm{COO}^{-}(a q)+\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{OH}(a q)\) was measured at several temperatures, and the following data were collected: $$ \begin{array}{ll} \hline \text { Temperature }\left({ }^{\circ} \mathrm{C}\right) & k\left(\mathrm{M}^{-1} \mathrm{~s}^{-1}\right) \\ \hline 15 & 0.0521 \\ 25 & 0.101 \\ 35 & 0.184 \\ 45 & 0.332 \end{array} $$ Using these data, graph \(\ln k\) versus \(1 / T\). Using your graph, determine the value of \(E_{g}\)

The reaction $$ \mathrm{SO}_{2} \mathrm{Cl}_{2}(g) \longrightarrow \mathrm{SO}_{2}(g)+\mathrm{Cl}_{2}(g) $$ is first order in \(\mathrm{SO}_{2} \mathrm{Cl}_{2}\). Using the following kinetic data, determine the magnitude of the first-order rate constant: $$ \begin{array}{rl} \hline \text { Time (s) } & \text { Pressure } \mathrm{SO}_{2} \mathrm{Cl}_{2} \text { (atm) } \\ \hline 0 & 1.000 \\ 2,500 & 0.947 \\ 5,000 & 0.895 \\ 7,500 & 0.848 \\ 10,000 & 0.803 \\ \hline \end{array} $$

The first-order rate constant for reaction of a particular organic compound with water varies with temperature as follows: $$ \begin{array}{ll} \hline \text { Temperature (K) } & \text { Rate Constant (s }^{-1} \text { ) } \\\ \hline 300 & 3.2 \times 10^{-11} \\ 320 & 1.0 \times 10^{-9} \\ 340 & 3.0 \times 10^{-8} \\ 355 & 2.4 \times 10^{-7} \\ \hline \end{array} $$ From these data, calculate the activation energy in units of \(\mathrm{kJ} / \mathrm{mol}\).

The enzyme invertase catalyzes the conversion of sucrose, a disaccharide, to invert sugar, a mixture of glucose and fructose When the concentration of invertase is \(4.2 \times 10^{-7} M\) and the concentration of sucrose is \(0.0077 M\), invert sugar is formed at the rate of \(1.5 \times 10^{-4} \mathrm{M} / \mathrm{s} .\) When the sucrose concentration is doubled, the rate of formation of invert sugar is doubled also. (a) Assuming that the enzyme- substrate model is operative, is the fraction of enzyme tied up as a complex large or small? Explain. (b) Addition of inositol, another sugar, decreases the rate of formation of invert sugar. Suggest a mechanism by which this occurs.

See all solutions

Recommended explanations on Chemistry Textbooks

View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.