Question

In comparing gases with liquids, gases have ________ compressibility and ________ density.

A)greater; smaller

B)greater; greater

C)smaller; smaller

D)smaller; greater

E)none of the above

Answer 1

A) greater; smaller

Reason Compresibility: in gases the molecules are very far apart so they can be pushed closer. in liquids or solids they are already about as close as they can get unless the pressure is truly extreme.

Reason Density: The only comparison that makes sense is to compare the same substance in all three phases. Water is a common substance, but a bit unusual because it is more dense as a liquid than as a solid. This is why ice floats. Most substances are most dense as a solid. The density decreases somewhat as a liquid and when it is in the gas phase it is much less dense. In each phase the same mass of the substance will occupy more space (have a greater volume).