14. A compound composed of hydrogen and oxygen is analyzed and a sample of the compound
yields 0.59 g of hydrogen and 9.40 g of oxygen. The molecular mass of this compound is 3.40
g/mole. Find the empirical formula and the molecular formula of the compound.
Answers
Explanation:
But we must interrogate the
empirical formula
, and then use the quoted molecular mass to calculate the
molecular formula...
And thus for the given mass of compound we gots....
0.590
⋅
g
1.00794
⋅
g
⋅
m
o
l
−
1
=
0.585
⋅
m
o
l
with respect to hydrogen....
and
9.40
⋅
g
15.00
⋅
g
⋅
m
o
l
−
1
=
0.585
⋅
m
o
l
with respect to oxygen....
And thus we get the
empirical formula,
the simplest whole number ratio representing constituent atoms in a species of ...
H
0.585
⋅
m
o
l
0.585
⋅
m
o
l
O
0.585
⋅
m
o
l
0.585
⋅
m
o
l
=
H
O
...
But it is a fact that the
molecular formula
is a simple whole number multiple of the
empirical formula.
.
And thus in terms of the given
molecular mass....
34.00
⋅
g
⋅
m
o
l
−
1
=
n
×
{
1.00794
+
15.999
}
⋅
g
⋅
m
o
l
−
1
...where of course
1.00794
⋅
g
⋅
m
o
l
−
1
and
15.999
⋅
g
⋅
m
o
l
−
1
are the respective ATOMIC masses of hydrogen and oxygen....
And so
n
=
34.00
⋅
g
⋅
m
o
l
−
1
{
1.00794
+
15.999
}
⋅
g
⋅
m
o
l
−
1
Clealry,
n
=
2
, and the
molecular formula
≡
H
2
O
2
,
hydrogen peroxide
as we anticipated.....