Which statement best describes the difference between solids, liquids, and gases?

Which statement best describes the difference between solids, liquids, and gases?

• A. Solids have definitive shape and volume; liquids have definite volume but take shape of container; gases have neither definite shape nor volume.
• B. Liquids have definite shape but no volume.
• C. Gases have a definite volume and shape.
• D. Solids, liquids, and gases all have the same shape and volume.

Answer: (A)

Particles in different states behave differently, which explains why shapes and volumes vary. In a solid, the particles are tightly packed and vibrate in place, so the object has a definite shape and a definite volume. In a liquid, the particles glide past each other, so the substance keeps a definite volume but can flow and take the shape of its container. In a gas, the particles are far apart and move freely, spreading to fill both the space and the volume available, so there is no fixed shape or volume. That’s why the statement describing solids with definite shape and volume, liquids with definite volume but shape of the container, and gases with neither definite shape nor volume is the best description. The other ideas don’t fit because liquids do have volume, gases don’t have a fixed volume or shape, and not all states share the same shape and volume.

Particles in different states behave differently, which explains why shapes and volumes vary. In a solid, the particles are tightly packed and vibrate in place, so the object has a definite shape and a definite volume. In a liquid, the particles glide past each other, so the substance keeps a definite volume but can flow and take the shape of its container. In a gas, the particles are far apart and move freely, spreading to fill both the space and the volume available, so there is no fixed shape or volume.

That’s why the statement describing solids with definite shape and volume, liquids with definite volume but shape of the container, and gases with neither definite shape nor volume is the best description. The other ideas don’t fit because liquids do have volume, gases don’t have a fixed volume or shape, and not all states share the same shape and volume.