/*! 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 87 The standard enthalpies of forma... [FREE SOLUTION] | 91影视

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Chapter 18: Problem 87

The standard enthalpies of formation of \(\mathrm{ClO}\) and \(\mathrm{ClO}_{2}\) are 101 and \(102 \mathrm{~kJ} / \mathrm{mol}\), respectively. Using these data and the thermodynamic data in Appendix \(C\), calculate the overall enthalpy change for each step in the following catalytic cycle: $$ \begin{aligned} &\mathrm{ClO}(g)+\mathrm{O}_{3}(g) \longrightarrow \mathrm{ClO}_{2}(g)+\mathrm{O}_{2}(g) \\ &\mathrm{ClO}_{2}(g)+\mathrm{O}(g) \longrightarrow \mathrm{ClO}(g)+\mathrm{O}_{2}(g) \end{aligned} $$ What is the enthalpy change for the overall reaction that results from these two steps?

Short Answer

Expert verified
The overall enthalpy change for the reaction can be calculated by first determining the enthalpy changes for each step in the catalytic cycle using Hess's Law: For Step 1: 鈭咹鈧� = [鈭咹f(ClO鈧�) + 鈭咹f(O鈧�)] - [鈭咹f(ClO) + 鈭咹f(O鈧�)] For Step 2: 鈭咹鈧� = [鈭咹f(ClO) + 鈭咹f(O鈧�)] - [鈭咹f(ClO鈧�) + 鈭咹f(O)] Then, the enthalpy change for the overall reaction (鈭咹_total) is calculated by summing the enthalpy changes of both steps: 鈭咹_total = 鈭咹鈧� + 鈭咹鈧�

Step by step solution

01

Determine the enthalpies of formation for the other compounds

Use the thermodynamic data in Appendix C to find the standard enthalpies of formation for O鈧�, O鈧�, and O. These values are needed to apply Hess's Law in the following steps.
02

Calculate the enthalpy change for the first step in the cycle

Using Hess's Law, calculate the enthalpy change for the first reaction: ClO(g) + O鈧�(g) 鈫� ClO鈧�(g) + O鈧�(g) The enthalpy change for this step (鈭咹鈧�) can be calculated using the formula: 鈭咹鈧� = [鈭咹f(ClO鈧�) + 鈭咹f(O鈧�)] - [鈭咹f(ClO) + 鈭咹f(O鈧�)] Plug in the given values and the values obtained from Appendix C to find 鈭咹鈧�.
03

Calculate the enthalpy change for the second step in the cycle

Using Hess's Law, calculate the enthalpy change for the second reaction: ClO鈧�(g) + O(g) 鈫� ClO(g) + O鈧�(g) The enthalpy change for this step (鈭咹鈧�) can be calculated using the formula: 鈭咹鈧� = [鈭咹f(ClO) + 鈭咹f(O鈧�)] - [鈭咹f(ClO鈧�) + 鈭咹f(O)] Plug in the given values and the values obtained from Appendix C to find 鈭咹鈧�.
04

Calculate the enthalpy change for the overall reaction

To find the enthalpy change for the overall reaction (鈭咹_total), add the enthalpy changes of both steps: 鈭咹_total = 鈭咹鈧� + 鈭咹鈧� Once you have found 鈭咹_total, the overall enthalpy change for the reaction is obtained.

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Most popular questions from this chapter

Which of the following reactions in the stratosphere cause an increase in temperature there? (a) \(\mathrm{O}(\mathrm{g})+\mathrm{O}_{2}(g) \longrightarrow \mathrm{O}_{3}{ }^{*}(\mathrm{~g})\) (b) \(\mathrm{O}_{3}^{*}(g)+\mathrm{M}(g) \longrightarrow \mathrm{O}_{3}(g)+\mathrm{M}^{*}(g)\) (c) \(\mathrm{O}_{2}(\mathrm{~g})+h \mathrm{w} \longrightarrow 2 \mathrm{O}(\mathrm{g})\) (d) \(\mathrm{O}(\mathrm{g})+\mathrm{N}_{2}(\mathrm{~g}) \longrightarrow \mathrm{NO}(\mathrm{g})+\mathrm{N}(\mathrm{g})\) (e) All of the above

In the following three instances which choice is greener in a chemical process? Explain. (a) A reaction that can be run at \(350 \mathrm{~K}\) for \(12 \mathrm{~h}\) without a catalyst or one that can be run at \(300 \mathrm{~K}\) for \(1 \mathrm{~h}\) with a reusable catalyst. (b) A reagent for the reaction that can be obtained from corn husks or one that is obtained from petroleum. (c) A process that produces no by-products or one in which the by-products are recycled for another process.

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A friend of yours has seen each of the following items in newspaper articles and would like an explanation: (a) acid rain, (b) greenhouse gas, (c) photochemical smog, (d) ozone depletion. Give a brief explanation of each term and identify one or two of the chemicals associated with each. s in this respect?

The enthalpy of evaporation of water is \(40.67 \mathrm{~kJ} / \mathrm{mol}\). Sunlight striking Earthis surface supplies 168 W per square meter \((1 \mathrm{~W}=1 \mathrm{watt}=1 \mathrm{~J} / \mathrm{s})\). (a) Assuming that evaporation of water is due only to energy input from the Sun, calculate how many grams of water could be evaporated from a \(1.00\) square meter patch of ocean over a 12 -h day. (b) The specific heat capacity of liquid water is \(4.184 \mathrm{~J} / \mathrm{g}{ }^{\circ} \mathrm{C}\). If the initial surface temperature of a \(1.00\) square meter patch of ocean is \(26{ }^{\circ} \mathrm{C}\), what is its final temperature after being in sunlight for \(12 \mathrm{~h}\), assuming no phase changes and assuming that sunlight penetrates uniformly to depth of \(10.0 \mathrm{~cm}\) ?
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