DOC.
639
OCTOBER
1918 679
If
the
specif.
wt.
of
anhydr.
MgSO4
is
calculated from
that
of
Epsom
salt,
as
for Glauber’s salt,
the
result found
is 4.7,
hence
the
molecular volume at
0.21;
whereas
a
spec.
w.
of 2.67 would result from the solvent’s increase in volume for
this solution.-Whichever
volume
is
inserted in
the
formula for
V',
neither with
K
=
2.5
nor
with K
=
5
do
we
succeed
in
obtaining
the
observed
numerical values
for
n'. Well,
I performed
the
calculation for
the
case
that the
volume of the
MgSO4
in solution
is apparently
enlarged by
the
entry of
H2O.
The
resulting
behavior
of
the
volume increase would
then
correspond
to
the addition
of
2 H2O’s
to
the
MgSO4
molecule
(molecular
volume
0.38),
the
friction, however, to
the addition
of
4
H2O’s,
or
7
H2O’s,
resp.:
Solution
%
Upon
Addition
n'
Calculated
n'
Obs.
of
MgSO4
of
(K
=
5)
2%
4
H2O
50.9
s
50.4
4%
"
54.7 54.5
6%
"
58.6
58.6 58
10%
" 66.3 67
14% 4
H2O
74.8
5
” 79.5
6 ” 84.5
82.7
7 ” 89.1
16% 7 H20 94.5 97
(Epsom salt)
20% " 111.3 114.5
It
would
naturally
be of
great
im-
portance
to
come
to know
the
spec,
wts.
of
the
Mg
sulfates of
differing
crystallization-water
content,
and fur-
thermore
to know
which sorts
crys-
tallize out of
the
solutions.
The
fact
that the
high
concentrations
16%
and
20%
exhibit
a
friction
equaling
the
quantity
that the
dissolved
amount
of
MgSO4
would have
as
Epsom
salt,
agrees
with
the
behavior of
Epsom
salt
solutions,
of
which it
had
to
be
assumed,
of
course,
that
the
crystallization
water remains within
the
molecular bond.
Copper
chloride
CuCl2
-I-
2
H20:
Spec.
wt. 2.4. Mol. wt. 170.8
(thereof
CuCl2
134.5
and
2
H20
36.03). According
to
the
one
result,
I
found Cu
63.6,
according
to
the
other,
63.12;
likewise
for
Cl,
35.45
on
the
one
hand, 35.18
on
the
other.
That
is
why
I
took
as a
basis for
the
calculations
the total
mol. wt.
170,
of
this
CuCl2
134.