Why is a gas easier to compress than a liquid or a solid?

1 Answer
Apr 18, 2017

Because most of the volume of a gas is empty space.........

Explanation:

We can use the Ideal Gas Equation to approximate gaseous density:

PV=nRT, so P/(RT)=n/V

But n="mass"/"molar mass"

And so P/(RT)xx"molar mass"="mass"/V=rho.

And thus for a given gas rho is proportional to "pressure", and inversely proportional to "absolute temperature".

On the other hand, in condensed phases, there is little dead space between atoms and molecules. And thus the volumes (and densities) of the condensed phases are essentially constant.