Solids and liquid are collectively known as condensed phases.Explain.
Answers
SOLIDS AND LIQUIDS HAVE MUCH SMALLER PARTICLES AS COMPARED TO THOSE IN GASES. HENCE THEY ARE COLLECTIVELY KNOWN AS CONDENSED PHASE.
If the ratio of the gas volume to liquid volume is 1000, then the ratio of the distance between the
molecules in the gas to that between those in the l
iquid is the cube root of the volume ratio, that is,
ten. The molecules of the gas are ten times farther apart on the average than are those of the
liquid. The distance between molecules in the liquid is roughly equal to the molecular diameter;
hence, in
the gas the molecules are separated by a distance which is, on the average, ten times their
diameter. This large spacing in the gas compared with that in the liquid results in the
characteristic properties of the gas and the contrast of these properties
with those of the liquid.
This comes about simply because of the short
-
range nature
of the intermolecular forces, the van
der Waals forces. The effect of these forces decreases very sharply with increase in distance
between the molecules and falls to an
almost negligible value at distances of four to five times the
molecular diameter. If we measure the forces by the magnitude of the term a/
2
in the van der
Waals equation, then an increase in volume by a factor by a factor of 1000 in going from liquid to
gas decreases the term by a factor of 10
6
. Conversely, in the liquid the effect of the van der Waal;s
forces is a million times larger than it is in the ga
s.