44ln ln 593 jk 100 373 273 s sa sb

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T

 Note
that
if
the
pressure
at
which
this
transformation
takes
place
is
1
bar,
 then
the
enthalpy
change
is
the
standard
phase
transformation
enthalpy
at
 the
phase
transformation
temperature
(or
the
latent
enthalpy
of
phase
 transformation)
and
T
is
the
phase
transformation
temperature.
For
 Marand’s
Notes:
Chapter
3
‐
The
Second
Law
of
Thermodynamics
 100
 example
for
the
ice
to
water
transformation,
it
occurs
reversibly
at
1
atm
 only
at
a
temperature
of
0°C.
Similarly,
the
water
liquid
to
water
vapor
 phase
transformation
takes
place
reversibly
at
1
atm
only
at
the
boiling
 point
which
is
100°C.

You
could
obviously
put
water
liquid
in
a
freezer
at
‐ 10°C
and
force
the
phase
transformation
between
water
and
ice.
However,
 in
this
case,
it
would
not
occur
reversibly.
It
would
be
a
spontaneous
 transformation
and
the
entropy
change
cannot
be
calculated
as
shown
 above.
In
this
case,
we
will
show
below
how
a
reversible
path
can
be
 envisioned
between
the
initial
and
final
states
of
the
real
process.
 
 Note
also,
that
according
to
the
expression
for
the
entropy
change
 associated
with
a
phase
transformation
from
solid
to
liquid
or
from
liquid
to
 vapor,
the
sign
of
the
entropy
change
is
the
same
as
the
sign
of
the
 enthalpy
change
(it
is
positive
as
one
transforms
a
lower
temperature
 phase
to
a
higher
temperature
phase).
This
is
consistent
with
the
notion
 that
entropy
is
a
measure
of
disorder
(the
vapor
state
is
more
disordered
 than
the
liquid
state
and
the
liquid
state
is
more
disordered
than
the
solid
 state).
 
 
 Marand’s
Notes:
Chapter
3
‐
The
Second
Law
of
Thermodynamics
 101
 Entropy
Changes
for
Irreversible
Processes:
 To...
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This note was uploaded on 01/26/2014 for the course CHEM 3615 taught by Professor Aresker during the Spring '07 term at Virginia Tech.

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