Domanda del libro di testo
(a) What is the difference between a state and a microstate of a system?
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Ch.19 - Chemical Thermodynamics
Brown15th EditionChemistry: The Central ScienceISBN: 9780137542970
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TOC.tableOfContents
- Ch.1 - Introduction: Matter, Energy, and Measurement146
- Ch.2 - Atoms, Molecules, and Ions200
- Ch.3 - Chemical Reactions and Reaction Stoichiometry176
- Ch.4 - Reactions in Aqueous Solution155
- Ch.5 - Thermochemistry126
- Ch.6 - Electronic Structure of Atoms131
- Ch.7 - Periodic Properties of the Elements126
- Ch.8 - Basic Concepts of Chemical Bonding123
- Ch.9 - Molecular Geometry and Bonding Theories143
- Ch.10 - Gases147
- Ch.11 - Liquids and Intermolecular Forces91
- Ch.12 - Solids and Modern Materials122
- Ch.13 - Properties of Solutions126
- Ch.14 - Chemical Kinetics174
- Ch.15 - Chemical Equilibrium101
- Ch.16 - Acid-Base Equilibria139
- Ch.17 - Additional Aspects of Aqueous Equilibria146
- Ch.18 - Chemistry of the Environment72
- Ch.19 - Chemical Thermodynamics129
- Ch.20 - Electrochemistry142
- Ch.21 - Nuclear Chemistry101
- Ch.22 - Chemistry of the Nonmetals68
- Ch.23 - Transition Metals and Coordination Chemistry66
- Ch.24 - The Chemistry of Life: Organic and Biological Chemistry10
Brown15th EditionChemistry: The Central ScienceISBN: 9780137542970Non è quello che usi tu?Cambia libro di testo
Capitolo 19, Problema 29b
For the isothermal expansion of a gas into a vacuum, ΔE = 0, q = 0, and w = 0. (b) Explain why no work is done by the system during this process.
Guida verificata passo dopo passo1
insert step 1> Understand the concept of isothermal expansion into a vacuum, which is also known as free expansion.
insert step 2> Recognize that in a vacuum, there is no external pressure opposing the expansion of the gas.
insert step 3> Recall that work done by a gas during expansion is given by the formula: w = -P_{ext} \(\Delta\) V, where P_{ext} is the external pressure.
insert step 4> Since the gas is expanding into a vacuum, P_{ext} = 0, meaning there is no opposing force.
insert step 5> Conclude that with P_{ext} = 0, the work done, w, is also 0, as w = -0 \(\times\) \(\Delta\) V = 0.
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Isothermal Process
An isothermal process occurs at a constant temperature, meaning that the internal energy of an ideal gas remains unchanged during the expansion or compression. In this scenario, since the temperature is constant, any heat added to the system is used to do work, but in the case of expansion into a vacuum, there is no heat exchange with the surroundings.
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04:20
Spontaneity of Processes
Work in Thermodynamics
In thermodynamics, work is defined as the energy transfer that occurs when a force is applied over a distance. For a gas expanding against an external pressure, work is done by the system. However, in an expansion into a vacuum, there is no opposing pressure, meaning the gas does not push against anything, resulting in zero work done.
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01:18First Law of Thermodynamics
First Law of Thermodynamics
The First Law of Thermodynamics states that energy cannot be created or destroyed, only transformed. In the case of the isothermal expansion into a vacuum, the change in internal energy (ΔE) is zero, indicating that the energy remains constant. Since no work is done and no heat is exchanged, the system's energy balance confirms that ΔE = q + w = 0.
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01:18First Law of Thermodynamics
Pratica correlata
Domanda del libro di testo
(c) In a particular spontaneous process, the number of microstates available to the system decreases. What can you conclude about the sign of ΔSsurr?
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Domanda del libro di testo
(a) What sign for Δ𝑆 do you expect when the pressure on 0.600 mol of an ideal gas at 350 K is increased isothermally from an initial pressure of 0.750 atm?
(b) If the final pressure on the gas is 1.20 atm, calculate the entropy change for the process.
(c) Which of the following statements about this process are true? (i) The entropy change you calculated will be the same for at any other constant temperature. (ii) The value of Δ𝑆 you calculated is valid only if the compression is done irreversibly. (iii) If the number of moles of gas being compressed were decreased by a factor of three, the entropy change would increase by a factor of three.
Domanda del libro di testo
(b) As a system goes from state A to state B, its entropy decreases. What can you say about the number of microstates corresponding to each state?
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Domanda del libro di testo
(c) During a certain reversible process, the surroundings undergo an entropy change, ΔSsurr = -78 J/K. What is the entropy change of the system for this process?
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Domanda del libro di testo
(b) In a particular spontaneous process the entropy of the system decreases. What can you conclude about the sign and magnitude of ΔSsurr?
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