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Ch.10 - Gases: Their Properties & Behavior
Chapter 10, Problem 37

Why are gases so much more compressible than solids or liquids?

Verified step by step guidance
1
Step 1: Understand the basic structure of matter in different states. Solids have particles that are closely packed in a fixed arrangement, liquids have particles that are close but can move past each other, and gases have particles that are far apart and move freely.
Step 2: Recognize that compressibility is the ability of a substance to decrease in volume under pressure. This is largely determined by the amount of space between particles.
Step 3: Consider the particle arrangement in gases. In gases, particles are much farther apart compared to solids and liquids, meaning there is a lot of empty space between them.
Step 4: Realize that when pressure is applied to a gas, the particles can be pushed closer together because of the large amount of empty space, making gases highly compressible.
Step 5: Compare this to solids and liquids, where particles are already close together, leaving little room for compression, thus making them much less compressible than gases.

Key Concepts

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

Molecular Structure

Gases consist of widely spaced molecules that move freely and rapidly in all directions. This large distance between molecules allows for significant space to be occupied when pressure is applied, leading to high compressibility. In contrast, solids have tightly packed molecules in a fixed arrangement, while liquids have molecules that are closer than gases but still allow some movement.
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Intermolecular Forces

The strength of intermolecular forces plays a crucial role in the compressibility of substances. Gases experience weak intermolecular forces, allowing their molecules to be easily pushed closer together under pressure. In solids and liquids, stronger intermolecular forces resist compression, making them less compressible compared to gases.
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Ideal Gas Law

The Ideal Gas Law (PV=nRT) describes the relationship between pressure (P), volume (V), and temperature (T) of an ideal gas. It illustrates how gases can expand or compress significantly with changes in pressure and temperature, highlighting their compressibility. This law does not apply to solids and liquids in the same way, as their volume changes very little under pressure.
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