The correct option is **B. Gases are highly compressible and fill their containers uniformly.** ### Detailed Explanation: 1. **Understanding Gases:** - Gases are one of the three primary states of matter, alongside solids and liquids. The behavior of gases is governed by the kinetic molecular theory, which states that gas particles are in constant, random motion and are far apart from each other compared to solids and liquids. 2. **Compressibility:** - Gases are highly compressible because the particles are spaced far apart. When pressure is applied to a gas, the particles can be pushed closer together, significantly reducing the volume of the gas. This is in stark contrast to solids and liquids, which have fixed volumes and are not easily compressed due to the close proximity of their particles. 3. **Filling Containers:** - Gases fill their containers uniformly because the particles move freely and spread out to occupy the entire volume available to them. This means that regardless of the shape of the container, the gas will distribute evenly throughout it. This property is a direct result of the high kinetic energy of gas particles, which allows them to overcome intermolecular forces and move independently. ### Why Other Options Are Incorrect: - **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 liquids, which have a definite volume but take the shape of their container, gases will expand to fill the entire volume of their container. Therefore, they have neither a definite shape nor a definite volume. - **C. Gases have stronger intermolecular forces than solids.** - This statement is also incorrect. In fact, gases have much weaker intermolecular forces compared to solids and liquids. In solids, particles are held together by strong intermolecular forces, which give them a fixed structure. In liquids, the forces are weaker than in solids but still significant enough to keep the particles close together. In gases, the intermolecular forces are negligible, allowing particles to move freely and independently. - **D. Gases can only exist at high temperatures and pressures.** - This statement is misleading. While gases can exist at high temperatures and pressures, they can also exist at low temperatures and pressures. The state of matter (gas, liquid, or solid) depends on the temperature and pressure conditions, but gases can be found in a wide range of conditions, not just at high temperatures and pressures. ### Summary of Key Points: - Gases are highly compressible due to the large spaces between particles. - Gases fill their containers uniformly, spreading out to occupy the entire volume. - Gases have weaker intermolecular forces compared to solids and liquids. - Gases can exist under various temperature and pressure conditions, not just high ones. This understanding of gas behavior is crucial for various applications in chemistry, including gas laws, reactions involving gases, and understanding the behavior of gases in different environments.