A space-filling model shows the relative amount of space each atom takes up. In other words, a space-filling model can show relative sizes of atoms. However, unlike ball-and-stick or structural models, space-filling models do not show bond lengths clearly. Bonds are not really like sticks in a ball-and-stick model.
C) volume
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The volume of gas depends on e.g. temperature and pressure.
1) If the volume of a container is increased, the temperature increases. 2) If the volume of a container is decreased, the temperature decreases. This means that the volume of a gas is directly proportional to its temperature. ... If the amount of gas in a container is increased, the volume increases.