**Correct Option: C. Gas particles are loosely arranged and move freely, filling the container they occupy.** ### Detailed Explanation: To understand why option C is the correct answer, we need to look at the properties of gases and how they compare to solids and liquids. 1. **Particle Arrangement**: - In solids, particles are closely packed together in a fixed arrangement. They can only vibrate in place, which is why solids have a definite shape and volume. - In liquids, particles are still close together but can slide past one another, allowing liquids to take the shape of their container while maintaining a definite volume. - In gases, particles are much farther apart compared to solids and liquids. They are not arranged in any fixed pattern, which allows them to move freely. 2. **Movement of Gas Particles**: - Gas particles are in constant, rapid motion. This motion is random and allows them to fill the entire volume of their container. This is a key characteristic of gases: they expand to occupy the space available to them. - The kinetic energy of gas particles is high, which contributes to their ability to move freely and collide with each other and the walls of their container. 3. **Filling the Container**: - When gas is placed in a container, it spreads out to fill the entire volume of that container. This is due to the high energy and low intermolecular forces between gas particles, which allows them to overcome any attractions and move apart from each other. ### Why the Other Options are Incorrect: - **Option A: Gas particles are closely packed and vibrate in fixed positions.** - This statement describes solids, not gases. In gases, particles are not closely packed; they are far apart and do not vibrate in fixed positions. Instead, they move freely and randomly. - **Option B: Gas particles have a definite shape and volume.** - This is also incorrect. Gases do not have a definite shape or volume. They take the shape of their container and can expand to fill any volume. This is a fundamental property of gases. - **Option D: Gas particles are incompressible and cannot flow.** - This statement is false. Gases are compressible, meaning they can be compressed into a smaller volume when pressure is applied. Additionally, gases can flow, which is a characteristic that distinguishes them from solids and liquids. ### Summary of Key Points: - Gas particles are far apart and move freely, allowing them to fill the entire volume of their container. - Gases do not have a definite shape or volume; they adapt to the shape of their container. - The high kinetic energy of gas particles contributes to their ability to move and collide with one another. - Understanding the behavior of gas particles is crucial for grasping the differences between the three states of matter: solids, liquids, and gases. This comprehensive understanding of gas behavior is essential for further studies in chemistry, particularly in areas such as thermodynamics and gas laws.