**Correct Option: C. Gas particles are in constant, random motion and fill the volume of the container.** ### Detailed Explanation: 1. **Understanding Gas Behavior:** - Gases are one of the three primary states of matter, alongside solids and liquids. The behavior of gas particles is fundamentally different from that of particles in solids and liquids. - In a gas, particles are not held together by strong intermolecular forces, which allows them to move freely and independently. 2. **Constant, Random Motion:** - Gas particles are in constant motion. This means they are always moving in various directions at high speeds. The motion is random, meaning that the direction and speed of each particle can change at any moment. - This constant motion is a key characteristic of gases and is a result of the high kinetic energy that gas particles possess. 3. **Filling the Volume of the Container:** - When gas particles are placed in a closed container, they will spread out to fill the entire volume of that container. This is because they move freely and collide with the walls of the container, exerting pressure. - The ability of gas particles to fill the container is a direct consequence of their random motion and lack of strong intermolecular forces. ### Why the Other Options are Incorrect: - **Option A: Gas particles are tightly packed and vibrate in fixed positions.** - This statement describes the behavior of solid particles, not gas particles. In solids, particles are closely packed together and can only vibrate in place due to strong intermolecular forces. Gases do not have this fixed arrangement. - **Option B: Gas particles are loosely connected and slide past one another.** - This option is more characteristic of liquids. In liquids, particles are close together but can move past one another, allowing liquids to flow. Gases, however, do not have any significant intermolecular forces keeping them together, so they do not "slide" past each other; they move freely and independently. - **Option D: Gas particles have a definite shape and volume.** - This statement is incorrect for gases. Gases do not have a definite shape or volume; they take the shape and volume of their container. This is a fundamental property of gases, distinguishing them from solids (which have a definite shape and volume) and liquids (which have a definite volume but take the shape of their container). ### Summary of Key Concepts: - **Gas particles are in constant, random motion** and do not have fixed positions. - **Gases fill the entire volume of their container** due to the freedom of movement of their particles. - **Gases do not have a definite shape or volume**, unlike solids and liquids. - Understanding the behavior of gas particles is crucial for grasping concepts in gas laws and thermodynamics. ### Common Pitfalls to Avoid: - Confusing the behavior of gases with that of solids or liquids. - Forgetting that gas particles are not influenced by strong intermolecular forces, which allows them to move freely. - Misunderstanding the concept of pressure in gases, which arises from the collisions of gas particles with the walls of their container. By keeping these points in mind, you can better understand the unique properties and behaviors of gases in various contexts.