Question

which postulate of the kinetic-molecular theory applies to the particles of a liquid?
○ they do not move freely but vibrate in a stationary position.
○ they can be compressed, which causes a large change in volume.
○ they have so much kinetic energy that their intermolecular forces are negligible.
○ they have enough kinetic energy to easily slide by each other.

Explanation:

1. Analyze the first option: Particles that vibrate in a stationary position describe solids (due to strong intermolecular forces confining them), not liquids. So this is incorrect.
2. Analyze the second option: Liquids are nearly incompressible (particles are close together), so a large change in volume upon compression does not apply to liquids. Gases are compressible, so this is incorrect.
3. Analyze the third option: If intermolecular forces are negligible, the substance is a gas (where particles move freely with high kinetic energy). Liquids have significant intermolecular forces, so this is incorrect.
4. Analyze the fourth option: Liquid particles have enough kinetic energy to move past (slide by) each other, which allows liquids to flow (unlike solids, where particles vibrate in place) and have a definite volume but no definite shape. This matches the kinetic - molecular theory postulate for liquids.

Answer:

D. They have enough kinetic energy to easily slide by each other.