Chemistry Reference
In-Depth Information
3.
[134 dm
3
]—
3H
2(g)
+ N
2(g)
2NH
3(g)
x dm
3
56.0 g
mass
molar mass
56.0 g
28.0 g/mole
A.
# of moles of N
2
=
=
= 2.00 moles
B. # of moles of H
2
can be determined from the molar ratio:
H
2
N
2
coefficients
# of moles
3
x
1
2.00
=
# of moles of H
2
= 6.00 moles
C. Volume of H
2
= # of moles × molar volume = 6.00 moles × 22.4 dm
3
/mole
= 134 dm
3
4.
[48.2 g of water]—
2H
2
O
2H
2
+ O
2
x g
30.
0
dm
3
volume
molar volume
30.0 d
m
3
22.4 dm
3
/mole
= 1.34 moles
A.
# of moles of O
2
=
=
B. # of moles of H
2
O can be determined from the molar ratio:
H
2
OO
2
coefficients
# of moles
2
x
1
1.34
=
# of moles of H
2
O = 2.68 moles
C. Mass of H
2
O = # of moles × molar mass = 2.68 moles × 18.0 g/mole = 48.2 g
5.
[18.7 dm
3
of hydrogen]—
2H
2
O
2H
2
+ O
2
15.0 g
x dm
3
mass
molar mass
15.0 g
18.0 g/mole
= 0.833 moles
A.
# of moles of H
2
O =
=
B. # of moles of H
2
can be determined from the molar ratio:
H
2
OH
2
coefficients
# of moles
2
0.833
=
2
x
# of moles of H
2
= 0.833 moles
C. Volume of H
2
= # of moles × molar volume = 0.833 moles × 22.4 dm
3
/mole
= 18.7 dm
3
6.
[8.00 g of oxygen]—
2H
2
O
2H
2
+ O
2
22.4 dm
3
x g
volume
molar volume
22.4 d
m
3
22.4 dm
3
/mole
= 1.00 moles
A.
# of moles of H
2
=
=
B. # of moles of O
2
can be determined from the molar ratio:
H
2
O
2
coefficients
2
1.00
=
1
x
# of moles
# of moles of O
2
= 0.500 moles
C. Mass of O
2
= # of moles × molar mass = 0.500 moles × 16.0 g/mole = 8.00 g
7.
[1.61 dm
3
of oxygen]—
2Mg + O
2
2MgO
3.50 g
x dm
3
mass
molar mass
3.50 g
24.3 g/mole
A.
# of moles of Mg =
=
= 0.144 moles
