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

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:

$P V = n R T$, so $\frac{P}{R T} = \frac{n}{V}$

But $n = \text{mass"/"molar mass}$

And so $\frac{P}{R T} \times \frac{\text{molar mass"="mass}}{V} = \rho$.

And thus for a given gas $\rho$ is proportional to $\text{pressure}$, and inversely proportional to $\text{absolute temperature}$.

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.