2
PHENOMENA OF
CAPILLARITY
From
these
equations
it follows that
This is,
however,
the total
energy
necessary to
form
a
unit surface.
Further,
we
form
The experimental
studies
have
shown
that
7
can
be represented
with
very
good
approximation
as
a
linear function of
temperature,
i.e.:
The
energy necessary
to
form
a
unit surface of
a
liquid
is
independent
of
the
temperature.
It also follows that
hence:
no
heat
content
should
be
ascribed
to
the surface
as
such;
rather, the
energy
of the surface is
of potential nature.
It
can
be
seen
already
that the
quantity
is
more
suited for stoichiometric
investigations
than is the hitherto
used
7
at
boiling
temperature. The
fact that the
energy
required
for
the
formation
of
a
unit surface
barely
varies with the
temperature
teaches
us
also that the
configuration
of molecules
in
the surface
layer will
not
vary
with
temperature
(apart from
changes
of
the order
of
magnitude
of thermal
expansion).
To
find
a
stoichiometric
relationship
for the
quantity
[3]
[4]
[5]
7+47-
s..l1)
-
______
r
OIslll
01w
~IILTJ
=
0
=-T
=4~+i~=fi-4~-T4~=O
-T43
7-Tfi