Question

Why are gases compressible but not liquids?

Answer 1

Hint: Compressibility is the measure of how much a given volume of the matter whether solid, liquid, or gas, decreases when placed under pressure. The degree of compressibility depends upon the intermolecular spacing between the particles of a matter. Greater the spacing between the particles, the more loosely packed the matter is and the higher is the chances of that matter to get compressed. This basic information can be used to answer why gases are compressible but not liquids.

Complete step-by-step solution:
Intermolecular spacing is directly proportional to the degree of compressibility of a matter. The more the space between the particles, the more will be the chances of compressing the constituent particle after the pressure is applied. The particles in a gas molecule are loosely packed and thus the intermolecular spacing between the particles of a gas is very large as compared to liquid as well as solid. Most of the volume of gas is composed of a large amount of empty space between the particles. At room temperature and standard pressure, the average distance between two gas molecules is about 10 times the diameter of the complete molecule itself. Thus, gases get compressed easily as compared to solids and liquids when pressure is applied.
Hence, gases are easily compressible but not liquids.

Note: Students must understand that although gases have more degree of compressibility it doesn’t mean that the liquids and solids cannot be compressed. They can also be compressed but a greater amount of pressure is to be applied in order to compress them. The particles in the solids are closer to each other as compared to liquids and gases. Thus, maximum force is applied to compress solids. Compression minimizes the space between the particles.