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Ch.19 - Chemical Thermodynamics
Chapter 19, Problem 31b

Would each of the following changes increase, decrease, or have no effect on the number of microstates available to a system: (b) decrease in volume

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Understand the concept of microstates: Microstates refer to the different ways in which the energy of a system can be distributed among its particles at a given energy level. The number of microstates ( ext{W}) is related to the entropy ( ext{S}) of the system, where higher microstates mean higher entropy.
Consider the effect of volume on microstates: When the volume of a system decreases, the particles are confined to a smaller space. This confinement limits the number of positions and orientations each particle can assume.
Relate volume decrease to particle movement: In a smaller volume, particles have less space to move around, which reduces the number of possible energy distributions among the particles.
Conclude the effect on microstates: Since the number of available positions and orientations for particles decreases with a decrease in volume, the number of microstates ( ext{W}) available to the system also decreases.
Link to entropy: A decrease in the number of microstates leads to a decrease in the entropy ( ext{S}) of the system, according to the formula ext{S} = k ext{ln} ext{W}, where ext{k} is the Boltzmann constant.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Microstates

Microstates refer to the specific configurations or arrangements of particles in a system that correspond to a particular macroscopic state. The number of microstates is crucial in statistical mechanics, as it relates to the entropy of the system. A higher number of microstates indicates greater disorder and higher entropy, while fewer microstates suggest more order and lower entropy.
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Entropy

Entropy is a measure of the disorder or randomness in a system. In thermodynamics, it quantifies the number of ways a system can be arranged while maintaining the same energy level. According to the second law of thermodynamics, the entropy of an isolated system tends to increase over time, reflecting a natural tendency towards greater disorder.
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Volume and Microstates

The volume of a system directly influences the number of available microstates. When the volume decreases, the space available for particles to occupy is reduced, which typically leads to a decrease in the number of possible arrangements of those particles. Consequently, this reduction in volume generally results in a decrease in entropy, as there are fewer microstates available for the system.
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