For the reaction $$\mathrm{X}+\mathrm{Y} \longrightarrow \mathrm{R}+\mathrm{Z} \quad \Delta H=+295 \mathrm{~kJ},$$ draw a reaction-energy diagram for the reaction if its activation energy is \(378 \mathrm{~kJ} .\)

Short Answer

Expert verified
Question: Draw and label a reaction-energy diagram for the chemical reaction $$\mathrm{X}+\mathrm{Y} \longrightarrow \mathrm{R}+\mathrm{Z}$$ with its enthalpy change (\(\Delta H\)) equal to \(+295 \mathrm{~kJ}\) and activation energy (\(E_a\)) equal to \(378 \mathrm{~kJ}\). Answer: To draw a reaction-energy diagram for the given reaction, follow these steps: 1. Draw the axes for the reaction-energy diagram, labeling the x-axis as "Reaction Progress" and the y-axis as "Energy." 2. Indicate the initial energy state of the reactants (point A) and the final energy state of the products (point B), with B being higher on the y-axis than A due to the positive enthalpy change. 3. Mark the point representing the activation energy (point C), which is \(378 \mathrm{~kJ}\) higher on the y-axis than point A. 4. Indicate the enthalpy change (295 kJ) between A and B. 5. Connect points A, C, and B with a smooth curve to create the reaction-energy diagram, showing the energy changes during the reaction.

Step by step solution

01

Draw the axes for the reaction-energy diagram

Begin by drawing the axes for the reaction-energy diagram. Label the x-axis as "Reaction Progress" and the y-axis as "Energy".
02

Indicate the initial and final energy states

On the y-axis, mark a point to represent the initial energy state of the reactants X and Y (let's call this point A). Similarly, mark a point to represent the final energy state of the products R and Z (let's call this point B). Since the enthalpy change, \(\Delta H\), is positive, the final energy state (B) will be higher on the y-axis than the initial energy state (A).
03

Indicate the activation energy

The activation energy, \(E_a\), is the energy required to initiate the reaction. This can be represented by a higher energy state compared to A. Measure up from point A and mark a point \(378 \mathrm{~kJ}\) higher on the y-axis (let's call this point C). This point represents the energy level of the activated complex or transition state.
04

Indicate the enthalpy change

The enthalpy change, \(\Delta H\), represents the difference in energy between the reactants and products. From the initial energy state A, measure up and mark the point that is \(295 \mathrm{~kJ}\) higher on the y-axis, which should correspond to point B.
05

Connect the points to form the reaction-energy diagram

Now, connect the points A, C, and B with a smooth curve to create the reaction-energy diagram. The curve should go from the initial energy state A to the transition state C, and then back down to the final energy state B. This represents the energy changes during the reaction. You now have a complete reaction-energy diagram for the given reaction.

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 Vaia!

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 decomposition of \(\mathrm{N}_{2} \mathrm{O}_{5}\) to \(\mathrm{NO}_{2}\) and \(\mathrm{NO}_{3}\) is a first-order gas-phase reaction. At \(25^{\circ} \mathrm{C}\), the reaction has a half-life of \(2.81\) s. At \(45^{\circ} \mathrm{C}\), the reaction has a half-life of \(0.313 \mathrm{~s}\). What is the activation energy of the reaction?

Experimental data are listed for the hypothetical reaction $$\mathrm{A}+\mathrm{B} \longrightarrow \mathrm{C}+\mathrm{D}$$ $$\begin{array}{lcccccc}\hline \text { Time (s) } & 0 & 10 & 20 & 30 & 40 & 50 \\\\{[\mathrm{~A}]} & 0.32 & 0.24 & 0.20 & 0.16 & 0.14 & 0.12 \\ \hline\end{array}$$ (a) Plot these data as in Figure \(11.2\). (b) Draw a tangent to the curve to find the instantaneous rate at \(30 \mathrm{~s}\). (c) Find the average rate over the 10 to \(40 \mathrm{~s}\) interval. (d) Compare the instantaneous rate at \(30 \mathrm{~s}\) with the average rate over the thirty-second interval.

In the first-order decomposition of acetone at \(500^{\circ} \mathrm{C}\), $$\mathrm{CH}_{3}-\mathrm{CO}-\mathrm{CH}_{3}(g) \longrightarrow \text { products }$$ it is found that the concentration is \(0.0300 \mathrm{M}\) after \(200 \mathrm{~min}\) and \(0.0200 \mathrm{M}\) after 400 min. Calculate the following. (a) the rate constant (b) the half-life (c) the initial concentration

The gas-phase reaction between hydrogen and iodine $$\mathrm{H}_{2}(g)+\mathrm{I}_{2}(g) \rightleftharpoons 2 \mathrm{HI}(g)$$ proceeds with a rate constant for the forward reaction at \(700^{\circ} \mathrm{C}\) of \(138 \mathrm{~L} / \mathrm{mol} \cdot \mathrm{s}\) and an activation energy of \(165 \mathrm{~kJ} / \mathrm{mol}\). (a) Calculate the activation energy of the reverse reaction given that \(\Delta H_{i}^{\circ}\) for HI is \(26.48 \mathrm{~kJ} / \mathrm{mol}\) and \(\Delta H_{i}^{\circ}\) for \(\mathrm{I}_{2}(\mathrm{~g})\) is \(62.44 \mathrm{~kJ} / \mathrm{mol}\). (b) Calculate the rate constant for the reverse reaction at \(700^{\circ} \mathrm{C}\). (Assume \(\mathrm{A}\) in the equation \(k=\mathrm{Ae}^{-\mathcal{P}_{2} / \mathrm{RT}^{\prime}}\) is the same for both forward and reverse reactions.) (c) Calculate the rate of the reverse reaction if the concentration of HI is \(0.200 M\). The reverse reaction is second-order in HI.

The decomposition of ethane, \(\mathrm{C}_{2} \mathrm{H}_{6}\), is a first-order reaction. It is found that it takes 212 s to decompose \(0.00839 \mathrm{M} \mathrm{C}_{2} \mathrm{H}_{6}\) to \(0.00768 \mathrm{M}\). (a) What is the rate constant for the reaction? (b) What is the rate of decomposition (in \(\mathrm{mol} / \mathrm{L} \cdot \mathrm{h}\) ) when \(\left[\mathrm{C}_{2} \mathrm{H}_{6}\right]=\) \(0.00422 \mathrm{M} ?\) (c) How long (in minutes) will it take to decompose \(\mathrm{C}_{2} \mathrm{H}_{6}\) so that \(27 \%\) remains? (d) What percentage of \(\mathrm{C}_{2} \mathrm{H}_{6}\) is decomposed after \(22 \mathrm{~min}\) ?

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.

Sign-up for free