Which of the following properties of gases distinguish them from liquids—that is, are unique to the gaseous phase of matter?

1. Gases fill the available space.
2. Gases exhibit viscosity.
3. Gases exert pressure.
4. Gases are readily compressed.
a. 2, 3, and 4 only
b. 1 and 3 only
c. 2 and 4 only
d. 1 and 4 only

ANS: D
Unlike liquids, gases are readily compressed and expanded and fill the spaces available to them by diffusion.