Chemistry Reference
In-Depth Information
B. # of moles of O
2
can be found with the molar ratio:
KCl
O
2
coefficients
# of moles
1
0.657
3
x
=
# of moles of O
2
(x) = 1.97 moles
C. Mass of O
2
= # of moles × molar mass = 1.97 moles × 32.0 g/mole = 63.0 g
7.
[572 g of H
2
O]—
CH
4
+ 2O
2
CO
2
+ 2H
2
O
255 g
x g
mass
molar mass
255 g
16.0 g/mole
A.
B. # of moles of H
2
O can be found with the molar ratio:
# of moles of CH
4
=
=
= 15.9 moles
CH
4
H
2
O
coefficients
# of moles
1
15.9
2
x
=
# of moles of H
2
O (x) = 31.8 moles
C. Mass of H
2
O = # of moles × molar mass = 31.8 moles × 18.0 g/mole = 572 g
8.
[416 g of H
2
O]—
C
3
H
8
+ 5O
2
3CO
2
+ 4H
2
O
255 g
x g
mass
molar mass
255 g
44.1 g/mole
# of moles of C
3
H
8
=
=
= 5.78 moles
A.
B. # of moles of H
2
O can be found with the molar ratio:
C
3
H
8
H
2
O
coefficients
# of moles
1
5.78
4
x
=
# of moles of H
2
O (x) = 23.1 moles
C. Mass of H
2
O = # of moles × molar mass = 23.1 moles × 18.0 g/mole = 416 g
Lesson 7-5 Review
1.
[98.8 dm
3
of hydrogen]—
3H
2(g)
+ N
2(g)
2NH
3(g)
dm
3
50.0 g
mass
molar mass
50.0 g
17.0 g/mole
A.
# of moles of NH
3
=
=
= 2.94 moles
B. # of moles of H
2
can be determined from the molar ratio:
H
2
NH
3
coefficients
# of moles
3
x
2
2.94
=
# of moles of H
2
= 4.41 moles
C. Volume of H
2
= # of moles × molar volume = 4.41 moles × 22.4 dm
3
/mole
= 98.8 dm
3
2.
[35.7 g of ammonia]—
3H
2(g)
+ N
2(g)
2NH
3(g)
23.5 dm
3
x g
volume
molar volume
23.5 d
m
3
22.4 dm
3
/mole
= 1.05 moles
A.
B. # of moles of NH
3
can be determined from the molar ratio:
# of moles of N
2
=
=
N
2
NH
3
coefficients
# of moles
1
1.05
2
x
=
# of moles of NH
3
= 2.10 moles
C. Mass of NH
3
= # of moles × molar mass = 2.10 moles × 17.0 g/mole = 35.7 g
