Which statement about gas particles is true?

Which statement about gas particles is true?

• A. Gas particles are randomly arranged and cannot move freely.
• B. Gas particles are far apart and can be compressed.
• C. Gas particles are touching and arranged in a fixed lattice.
• D. Gas particles have strong intermolecular forces keeping them close.

Answer: (B)

Gas particles move with considerable freedom and are separated by a lot of empty space. That large spacing means there isn’t a fixed arrangement and the particles can slide past one another and collide with container walls. Because there’s so much space, you can push them closer together and reduce the volume, i.e., compress the gas. This is a hallmark of gases: they are highly compressible and fill the space available to them. This idea also matches why gases behave differently from solids and liquids. In a solid, particles are touching and locked into a fixed lattice, so compression is minimal. In a liquid, particles are closer together and can flow but still aren’t freely far apart, so they don’t compress like gases. And in a gas, the intermolecular forces are weak enough that particles don’t stay close together, which is why they don’t remain in fixed positions and can be compressed.

Gas particles move with considerable freedom and are separated by a lot of empty space. That large spacing means there isn’t a fixed arrangement and the particles can slide past one another and collide with container walls. Because there’s so much space, you can push them closer together and reduce the volume, i.e., compress the gas. This is a hallmark of gases: they are highly compressible and fill the space available to them.

This idea also matches why gases behave differently from solids and liquids. In a solid, particles are touching and locked into a fixed lattice, so compression is minimal. In a liquid, particles are closer together and can flow but still aren’t freely far apart, so they don’t compress like gases. And in a gas, the intermolecular forces are weak enough that particles don’t stay close together, which is why they don’t remain in fixed positions and can be compressed.