Question

Explain why a gas can be compressed into a smaller volume but not a liquid

Answer 1

Gases dont have specific volumes i.e. they are spread out, they're particles disperse and therefore occupy the volume of the container allocated to it and so added pressure can easily force these particles into a more compact volume. Solids and liquids have more compact particles and so they are given little room to move so they are not easily compressed, think of a sponge its particles anre spread out so u can compress it, but a rock has tightly packed particles and so they cannot be compressed easily. 

in brief; the particles in gases are spread out more than those in a liquid or solid. Making them easier to compress. Liquids and solids are already more compact than a gas. 

Answer 2

Answer:

Compressibility is the measure of how much a given volume of matter decreases when placed under pressure. If we put pressure on a solid or a liquid, there is essentially no change in volume. The atoms, ions, or molecules that make up the solid or liquid are very close together.