Page 5 - 9-phy-7 Properties of Matter
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7. Properties of Matter eLearn.Punjab
LIQUIDS
The distances between the molecules of a liquid are slightly
more than in solids. Thus, attractive forces between them are
weaker. Like solids, molecules of a liquid also vibrate about
their mean position but are not rigidly held with each other.
Figure 7.4: Molecules are loosely packed in
liquids.
Due to the weaker attractive forces, they
Animation 7.3: States of Matter can slide over one another. Thus, the liquids
Source & Credit: Schools.bcsd can flow. The volume of a certain amount
of liquid remains the same, but because it
can flow, hence, it attains the shape of a container in which it is put.
GASES
Gases such as air have no fixed shape or
volume. They can be filled in any container
of any shape. Their molecules have random
motion and move with very high velocities.
Animation 7.4: States of Matter
Source & Credit: Schools.bcsd
Figure 7.5: Molecules are much farther In gases, molecules are much farther apart than solids or liquids
apart in gases. such as shown in figure-7.5. Thus, gases are much lighter than
solids and liquids. They can be squeezed into smaller volumes.
The molecules of a gas are constantly striking the walls of
a container. Thus, a gas exerts pressure on the walls of the
container.
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