Log out Go to App
Go to App

Learning Materials

Features

Discover

Chapter 19: Problem 110

The following processes were all discussed in Chapter 18 , "Chemistry of the Environment." Estimate whether the entropy of the system increases or decreases during each process: (a) photodissociation of \(\mathrm{O}_{2}(g),(\mathbf{b})\) formation of ozone from oxygen molecules and oxygen atoms, (c) diffusion of CFCs into the stratosphere, (d) desalination of water by reverse osmosis.

Short Answer

Expert verified
(a) The photodissociation of O2(g) increases the number of particles in the system, leading to an increase in entropy. (b) The formation of ozone from oxygen molecules and oxygen atoms decreases the number of particles in the system, leading to a decrease in entropy. (c) The diffusion of CFCs into the stratosphere increases entropy due to the increased dispersal of energy. (d) The desalination of water by reverse osmosis results in a more ordered state of the system, leading to a decrease in entropy.

Step by step solution

01

Process (a) Photodissociation of O2(g)

Photodissociation is the process of breaking a molecule into its constituent atoms or fragments under the influence of light. In the case of O2(g), the photodissociation process can be represented as follows: \[O_2(g) \xrightarrow{h \nu} 2O(g)\] As we can see, the number of particles in the system increases from 1 O2 molecule to 2 O atoms. An increase in the number of particles generally leads to an increase in entropy due to increased dispersal of energy. Therefore, the entropy of the system increases during this process.
02

Process (b) Formation of ozone from oxygen molecules and oxygen atoms

Ozone is formed from oxygen molecules and oxygen atoms via the following reaction: \[O_2(g) + O(g) \rightarrow O_3(g)\] In this case, two particles (one O2 molecule and one O atom) are combining to form one new particle (O3 molecule). A decrease in the number of particles generally leads to a decrease in entropy. Therefore, the entropy of the system decreases during this process.
03

Process (c) Diffusion of CFCs into the stratosphere

Diffusion is the process of particles spreading out from a region of high concentration to a region of lower concentration to reach a state of equilibrium. When CFCs (chlorofluorocarbons) diffuse into the stratosphere, their concentration decreases as they spread out among the other particles in the stratosphere, leading to an increase in entropy due to increased dispersal of energy. Therefore, the entropy of the system increases during this process.
04

Process (d) Desalination of water by reverse osmosis

Reverse osmosis is a process in which water is forced through a semi-permeable membrane to separate it from dissolved salts and impurities. In this process, water molecules that pass through the membrane are separated from the salt molecules and impurities, leading to a more ordered state of the system. This results in a decrease in entropy. Therefore, the entropy of the system decreases during this process.

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.

Start your free trial

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

Propanol \(\left(\mathrm{C}_{3} \mathrm{H}_{7} \mathrm{OH}\right)\) melts at \(-126.5^{\circ} \mathrm{C}\) and boils at \(97.4{ }^{\circ} \mathrm{C}\). Draw a qualitative sketch of how the entropy changes as propanol vapor at \(150^{\circ} \mathrm{C}\) and 1 atm is cooled to solid propanol at \(-150^{\circ} \mathrm{C}\) and \(1 \mathrm{~atm}\).

Use data from Appendix \(\mathrm{C}\) to calculate the equilibrium constant, \(K,\) at \(298 \mathrm{~K}\) for each of the following reactions: (a) \(\mathrm{H}_{2}(g)+\mathrm{I}_{2}(g) \rightleftharpoons 2 \mathrm{Hl}(g)\) (b) \(\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{OH}(g) \rightleftharpoons \mathrm{C}_{2} \mathrm{H}_{4}(g)+\mathrm{H}_{2} \mathrm{O}(g)\) (c) \(3 \mathrm{C}_{2} \mathrm{H}_{2}(g) \rightleftharpoons \mathrm{C}_{6} \mathrm{H}_{6}(g)\)

In each of the following pairs, which compound would you expect to have the higher standard molar entropy: (a) \(\mathrm{C}_{2} \mathrm{H}_{2}(g)\) or \(\mathrm{C}_{2} \mathrm{H}_{6}(g),(\mathbf{b}) \mathrm{CO}_{2}(g)\) or \(\mathrm{CO}(g) ?\) Explain.

For each of the following processes, indicate whether the signs of \(\Delta S\) and \(\Delta H\) are expected to be positive, negative, or about zero. (a) A solid sublimes. (b) The temperature of a sample of \(\mathrm{Co}(s)\) is lowered from \(60^{\circ} \mathrm{C}\) to \(25^{\circ} \mathrm{C}\). (c) Ethyl alcohol evaporates from a beaker. (d) A diatomic molecule dissociates into atoms. (e) A piece of charcoal is combusted to form \(\mathrm{CO}_{2}(g)\) and \(\mathrm{H}_{2} \mathrm{O}(g)\).

The normal freezing point of \(n\) -octane \(\left(\mathrm{C}_{8} \mathrm{H}_{18}\right)\) is \(-57{ }^{\circ} \mathrm{C}\). (a) Is the freezing of \(n\) -octane an endothermic or exothermic process? (b) In what temperature range is the freezing of \(n\) -octane a spontaneous process? (c) In what temperature range is it a nonspontaneous process? (d) Is there any temperature at which liquid \(n\) -octane and solid \(n\) -octane are in equilibrium? Explain.
See all solutions

Recommended explanations on Chemistry Textbooks

Chemistry Branches

Read Explanation

Chemical Analysis

Read Explanation

Ionic and Molecular Compounds

Read Explanation

Inorganic Chemistry

Read Explanation

Physical Chemistry

Read Explanation

Organic Chemistry

Read Explanation
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