Student Name: _______________________________________________ Pd. ____ Date: __________
Stoichiometry Word Problems 2 SOLUTIONS
1. Cellular respiration occurs in animal cells, a reaction that is essentially the combustion of a sugar
called glucose, C
6
H
12
O
6
. If the average human uses 550 liters of oxygen when breathing, how many
grams of glucose are used by this process?
Balanced Equation: C
6
H
12
O
6
+ 6 O
2
6 CO
2
+ 6 H
2
O
6126
2
6126
6126
2
6126
2
22
61.736
1
180
6
1
4.22
1
1
550 OHCg
OHCmol
OHCg
Omol
OHCmol
OL
OmolOL =
2. Nitroglycerin, C
3
H
5
(ONO
2
)
3
, was invented in 1846 by an Italian chemist named Ascanio Sobrero.
Nitroglycerine contains both an oxidant and a fuel. When it detonates, it decomposes to form carbon
dioxide, water, nitrogen, and oxygen, all in a gaseous state. Every mole of the explosive that
decomposes in this way generates a tremendous amount of energy – approximately 1.5 MJ (1 MJ = 1
megajoule = 1 x 10
6
J = 1 MJ).
a. If 1.135 kilograms of nitroglycerin detonates, how many total liters of gas (assuming
STP) are produced?
Balanced Equations: 4 C
3
H
5
(ONO
2
)
3
10 H
2
O + 12 CO
2
+ 6 N
2
+ O
2
3253
)(ONOHC812
1
4.22
4
29
227
1
1
1000
1
135.1 L
gasmol
gasL
nitromol
gasmol
nitrog
nitromol
nitrokg
nitrognitrokg =
b. How much energy is produced by the explosion?
MJ
nitromol
energyMJ
nitrog
nitromol
nitrokg
nitrognitrokg 5.7
1
1
227
1
1
1000
1
135.1 =
3. Sodium hydroxide is a strong, inexpensive base used commonly in many industrial chemical
processes. It is manufactured by creating a strong aqueous brine (NaCl) solution and applying an
intense electrical current. The sodium ions react with the water to generate sodium hydroxide,
hydrogen gas, and chlorine gas. If 2345 g of salt is mixed with 4562 g of water:
a. Which reactant is limiting?
Balanced Equation: 2 NaCl + 2 H
2
O 2 NaOH + H
2
+ Cl
2
OHg
OHmol
OHg
NaClmol
OHmol
NaClg
NaClmolNaClg
2
2
22
54.721
1
18
2
2
5.58
1
1
2345 =
Since the amount of H
2
O required is less than the amount provided (4562 g), it is in
excess, so NaCl is the limiting reagent.
