The correct option is **C. Gases expand to fill the shape and volume of their container.** ### Detailed Explanation: 1. **Understanding the States of Matter**: - Matter exists in three primary states: solids, liquids, and gases. Each state has distinct characteristics based on the arrangement and behavior of its particles. 2. **Characteristics of Gases**: - **Shape and Volume**: Gases do not have a definite shape or volume. Instead, they take the shape of their container and expand to fill the entire volume available. This is due to the high kinetic energy of gas particles, which allows them to move freely and spread out. - **Compressibility**: Gases are highly compressible compared to solids and liquids. This means that when pressure is applied, the volume of a gas can decrease significantly. - **Particle Arrangement**: In gases, particles are far apart and move independently of one another, unlike solids where particles are closely packed and only vibrate in place. 3. **Why Option C is Correct**: - Option C accurately describes the behavior of gases. When a gas is placed in a container, it will expand to fill the entire space, regardless of the container's shape or size. This characteristic is a fundamental property of gases and is a direct result of their particle behavior. ### Why the Other Options are Incorrect: - **Option A: Gases have a definite shape and volume.** - This statement is incorrect because gases do not have a definite shape or volume. Unlike solids, which maintain a fixed shape and volume, gases will conform to the shape of their container and will expand to fill the entire volume available. - **Option B: Gases are incompressible and have a fixed volume.** - This option is also incorrect. Gases are compressible, meaning their volume can change significantly under pressure. In contrast, liquids and solids are generally considered incompressible, maintaining a fixed volume regardless of pressure changes. - **Option D: Gases have particles that are tightly packed and vibrate in place.** - This statement describes solids rather than gases. In solids, particles are indeed tightly packed and can only vibrate in fixed positions. In gases, particles are not tightly packed; they are spaced far apart and move freely throughout the container. ### Summary of Key Points: - Gases expand to fill the shape and volume of their container. - Gases are compressible, unlike solids and liquids. - Gases have particles that are far apart and move independently. - Solids have a definite shape and volume, while gases do not. This understanding of the properties of gases compared to solids and liquids is crucial for grasping fundamental concepts in chemistry and physics.