About how many times as much volume does a gas occupy compared to the same substance as a liquid or solid under normal conditions

Gases don't have definite volume. Gas molecules occupy all available space.

Explanation:

Consider the example of water. Which is present in three state solid, liquid and gas. In the form of ice its volume is less as compared to the liquid and gas, because molecules are tightly packed. If we melt the same ice we observe the volume is increase because molecules are now apart from each other. The distance between the molecules of water increased. If the same amount of water is evaporated the molecule of water will occupy all available space , and the distance between the water molecules get increased and inter molecular forces becomes negligible.

Properties of gases:

Molecule of gases randomly move every where and occupy all available space.

Gases don't have definite volume and shape.

Their densities are very low as compared to the liquid and solids.

Gas molecules are at long distance from each other therefore by applying pressure gases can be compressed.

The very weak inter molecular forces are present between gas molecules.

Properties of Liquid:

Liquid have definite volume but don,t have definite shape.

Their densities are high as compared to the gases but low as compared to the solids.

In liquid, molecules are close to each other and have greater inter molecular forces as compared to the gas molecules.

Properties of solids:

Solids have definite volume and shape.

In solids molecules are tightly pack and very close to each other.

Their melting and boiling point are every high.

The densities of solids are also very high as compared to the liquid and gas.

There are very strong inter molecular forces are present between solid molecules.