Answer is 355 grams.
Explanation:
Given the molecular weights:
M
r
N
a
O
H
=
40
g
m
o
l
M
r
N
a
2
S
O
4
=
142
g
m
o
l
The analogy of the moles will be held constant:
n
N
a
O
H
n
N
a
2
S
O
4
=
2
1
n
N
a
O
H
n
N
a
2
S
O
4
=
2
For each one, substitute:
n
=
m
M
r
Therefore:
n
N
a
O
H
n
N
a
2
S
O
4
=
2
m
N
a
O
H
M
r
N
a
O
H
m
N
a
2
S
O
4
M
r
N
a
2
S
O
4
=
2
200
40
x
142
=
2
200
⋅
142
40
x
=
2
200
⋅
142
=
2
⋅
40
x
x
=
200
⋅
142
2
⋅
40
=
100
⋅
142
40
=
10
⋅
142
4
=
1420
4
=
=
710
2
=
355
g
r
a
m
s
(or just use a calculator)
Answer:
1
Explanation:
The empirical formula describes the simplest whole number ratio of each type of atom in a compound. To find this formula, you need to (1) convert grams of each element to moles (via their atomic masses) and then (2) find the ratio of each element (by dividing each molar value by the smallest mole value).
(Step 1)
Atomic Mass (Zn): 65.380 g/mol
Atomic Mass (C): 12.011 g/mol
Atomic Mass (O): 15.998 g/mol
10.40 grams Zn 1 mole
------------------------ x ------------------------ = 0.159 moles Zn
65.380 grams
1.92 grams C 1 mole
--------------------- x ----------------------- = 0.160 moles C
12.011 grams
7.68 grams O 1 mole
---------------------- x ------------------------ = 0.480 moles O
15.998 grams
(Step 2)
0.159 moles Zn / 0.159 = 1 atom Zn
0.160 moles C / 0.159 = 1 atom C
0.480 moles O / 0.159 = 3 atom O
The empirical formula is Zn₁C₁O₃. Therefore, the value that should be in the space is 1.
