Which of the following statements is true about the particles in a substance?

• A. They are stationary in solids and only move in liquids and gases.
• B. They do not interact with each other in any state of matter.
• C. They are always in constant motion, regardless of the state of matter.
• D. They have the same arrangement in solids, liquids, and gases.

Answer: (C)

Verified step by step guidance

1. Understand the concept of particle motion in different states of matter: In solids, particles are closely packed and vibrate in fixed positions. In liquids, particles are less tightly packed and can move past each other. In gases, particles are far apart and move freely at high speeds.
2. Analyze the first statement: 'They are stationary in solids and only move in liquids and gases.' This is incorrect because particles in solids vibrate in place; they are not stationary.
3. Analyze the second statement: 'They do not interact with each other in any state of matter.' This is incorrect because particles in solids, liquids, and gases interact to varying degrees. For example, intermolecular forces are strongest in solids and weakest in gases.
4. Analyze the third statement: 'They are always in constant motion, regardless of the state of matter.' This is correct because even in solids, particles vibrate, which means they are in constant motion.
5. Analyze the fourth statement: 'They have the same arrangement in solids, liquids, and gases.' This is incorrect because the arrangement of particles differs: solids have a fixed, orderly arrangement; liquids have a less orderly arrangement; and gases have a random, widely spaced arrangement.