676
DOC.
639
OCTOBER
1918
resp.;
n
the
number of
grams
of the salt
contained in
the solution.-I then
calcu-
lated the
quotient
b/2
for each
experiment.-
There
is,
first of
all,
Glauber’s
salt
Na2SO4
+
10 H2O,
about
which
I
have
ar-
rived at
the
view,
along
other
routes,
that it
releases its water of
crystallization–
which
according
to Werner’s
view
is, as you
know,
bound to
the central
atom
or
to
a
lateral
chain,[9]
thus
belonging
to
the
molecular bond-entirely
to
the
sol-
vent water.
It
comes
to
the
molecular
weight
of Glauber’s
salt
322.32,
of which
142.16
goes
to
Na2SO4
and
180.16
to
the
10
H2O’s.-
I
found
the
following
data
on
solubility:
100
cc
water dissolve
at 0°: 12.17
g
Na2SO4
+
10
H2O
and 5.02
g
anhydrous
Na2SO4.-
Now,
12.17
g
Na2SO4
+
10 H2O
contain
....
5.4
g
Na2SO4
and
6.77
g
water.
If
the latter
are
added
to
the
100
cc
water used
as a
solvent,
we
would have
5.4
g Na2SO4
in
106.77
cc
water
or
5.05
g
anhydrous
Na2SO4
in
100
cc,
which
agrees very
well
with
the
above
specification.
For
11°67
I found
specified as
the
solubility:
Na2SO4+
10
H2O..
26.38
g
in
100
g
water
” anhydrous 10.12g ” ” ” ”
.
26.38
g Na2SO4
+
10
H2O
contains
11.64
g Na2SO4
and
14.74
g
water. If
the
crystallization
water
escapes
from
the
molecular bond and
is
added to
the
solvent,
then
11.64
g
Na2SO4 are
contained in
114.74
g
water,
thus
10.14.
g
anhydrous
Na2SO4
in 100
g
water,
which
corresponds
to
the
observed solubility.-The cal-
culation
yields accordingly
at 32°73: 50.72
g
the
observation
50.65
g,
and at
40°15:
48.89
g
and
48.78
g
Na2SO4,
resp.-
At
32°73
the
Glauber’s
salt
melts
into
its
crystallization water
and from this
temperature
on
its
solubility drops
as
well.
At
this
temperature
the saturation
limit is reached at
322.32
g Na2SO4
+
10
H2O
to 100
g
water.
This number
is just
equal
to
the
molecular
weight
of
Glauber’s salt.
Therein,
322.32
•
142.16/322.32
=
142.16
g Na2SO4
and
322.32
.
180.16/322.32
=
180.16
g
water;
hence 142.16
g
anhydr.
Na2SO4
in
280.16
g
water
=
50.72
g
to
100
g
water,
which
corresponds
to
the saturation
value of
anhydrous Na2SO4.
The
behavior
of the
specific weight agrees
with
the
same
assumption.
I
found
in
this
regard
the
following
data:
Specif,
wt. of
a
10%
solution of
Na2SO4
+10
H2O
=
20%
" " " "
=
1.082
10%
” ”
Na2SO4 anhydrous
=
1.093.
In
the
10
g
Na2SO4
+
10 H2O
of
a
10%
Glauber’s
salt
solution,
4.4
g
Na2SO4
are
contained
and
5.6
g
water.
If
the latter
are
added to
the
90
g
solvent
water,