Stoichiometry
Mass-Volume
Volume-Mass
Volume-Volume
Stoichiometry in 3-D!
• We have already learned about these three
types of conversions:
– Mole-Mole
– Mass-Mole
– Mass-Mass
• There are three more types of stoichiometry
problems we will deal with today for gases:
– Mass-Volume
– Volume-Mass
– Volume-Volume
Molar Volume at STP
1 mol of a gas=22.4 L
at STP
Standard Temperature & Pressure
0°C and 1 atm
Molar Volume at STP
LITERS
OF GAS
AT STP
Molar Volume
(22.4 L/mol)
MASS
IN
GRAMS
Molar Mass
MOLES
(g/mol)
6.02 
1023
particles/mol
Molarity (mol/L)
LITERS
OF
SOLUTION
NUMBER
OF
PARTICLES
Mass-Volume Problems
• Step 1: Write a BALANCED EQUATION
• Step 2: Convert Known from mass to moles (molar mass)
• Step 3: Determine the mole ratio to convert from moles of
Known to moles of Unknown
• Step 4: Convert the Unknown substance from moles to
volume in liters (molarity or molar volume)
Mass-Volume Problems
Example:
2 H2 +
2 H 2O
O2
How many liters of oxygen are necessary to create 48.0 g H2O?
48.0 g H2O
1 mol H2O
1 mol O2
18.02 g H2O 2 mol H2O
22.4 L O2
1 mol O2
=
29.8 L O2
Mass-Volume Problem
Ni + FeSO4  Fe + NiSO4

What volume of a 0.5M NiSO4 solution is
produced from 5g of Ni?
5g Ni
1 mol
Ni
58.69
g Ni
1 mol
NiSO4
1 mol
Ni
1L
NiSO4
0.5 mol
NiSO4
=
.17L
NiSO4
Volume-Mass Problems
• Step 1: Write a BALANCED EQUATION
• Step 2: Convert Known substance from volume in liters
to moles (Molar Mass or Molarity)
• Step 3: Determine the mole ratio to convert from moles of
Known to moles of Unknown
• Step 4: Convert the Known substance from moles to mass
(Molar Mass)
Volume-Mass Problems
Example:
2 H2 +
2 H 2O
O2
How many grams of water are formed by reacting 36.0 L O2?
36.0 L O2
1 mol O2
2 mol H2O
22.4L O2
1 mol O2
18.02 g H2O
57.92 g
=
H 2O
1 mol H2O
Volume-Mass Problem
2AlCl3  2Al + 3Cl2

What mass of Al is produced from 5L of a
0.50M AlCl3 solution?
5L
AlCl3
.50 mol
AlCl3
2 mol
Al
1L
AlCl3
2 mol
AlCl3
26.98
g Al
1 mol
Al
=
67.45 g
Al
Volume-Volume Problems
• Step 1: Write a BALANCED EQUATION
• Step 2: Convert Known substance from volume in liters
to moles (molar volume or molarity)
• Step 3: Determine the mole ratio to convert from moles of
Known to moles of Unknown
• Step 4: Convert the Unknown substance from moles to
volume in liters (molar volume or molarity)
Volume-Volume Problems
Example:
2 H2 +
2 H 2O
O2
How many liters of H2 are required to react with 5.0 L O2?
5.0 L O2
1 mol O2
2 mol H2
22.4 L H2
22.4 L O2
1 mol O2
1 mol H2
=
10. L H2
Volume-Volume Problem
2AlCl3  2Al + 3Cl2

What volume of a .30M Al is produced
from 5L of a 0.50M AlCl3 solution?
5L
AlCl3
.50 mol
AlCl3
2 mol
Al
1L
AlCl3
2 mol
AlCl3
1L Al
=
.30
mol Al
8.33L Al