what is the experimental percent of oxygen in a copper oxide if 10g of copper reacted completely with 2.52g of oxygen?
Answers
Answer:
Explanation:
Recall that by using the molar mass of an element and the mass of the element in the sample, you can find the amount of moles in the sample. We're gonna find the moles of copper and oxygen within the sample of copper oxide.
Calculate the moles of copper given
Remember that moles
=
m
a
s
s
m
o
l
a
r
m
a
s
s
The molar mass of copper is
63.55
g
m
o
l
−
1
, as the atomic mass of an element corresponds to its molar mass in grams.
n
(
C
u
)
=
1.50
g
63.55
g
m
o
l
−
1
=
0.0236
...
m
o
l
C
u
Calculate the moles of oxygen in the final sample of copper oxide.
Mass of oxygen = mass of copper oxide - initial mass of copper
m
(
O
)
=
2.14
g
−
1.50
g
=
0.64
g
Molar mass of oxygen =
16.00
g
m
o
l
−
1
Now that we have the mass and the molar mass, we can work out the moles.
n
(
O
)
=
0.64
g
16.00
g
m
o
l
−
1
=
0.04
m
o
l
O
Now that we have the moles of copper and oxygen in the sample, compare the mole ratio.
C
u
:
O
=
0.0236
:
0.04
≈
3
:
5
Therefore, the empirical formula is
C
u
3
O
5
based on the data from the experiment.