Transcript Stoichiometry Notes Part II Multi-Step Problems From yesterday… Why are mole/mole problems impractical in a laboratory setting? We don’t ever measure directly in moles!

Stoichiometry Notes Part II
Multi-Step Problems
From yesterday…
Why are mole/mole
problems impractical in
a laboratory setting?
We don’t ever
measure directly in
moles!
Steps to solve every problem:
1)Write a balanced equation.
2)Put what you have over 1.
3)Convert into moles.
4)Compare using the mole to
mole ratio from the equation.
5)Convert into the unit the
question asks for.
Al + Cl2 a AlCl3
How many grams of aluminum
are needed to produce 22.7g
aluminum chloride?
Balance the equation first!!!
2 Al + 3 Cl2 a 2 AlCl3
How many grams of
aluminum are needed
to produce 22.7g
aluminum chloride?
2 Al + 3 Cl2 a 2 AlCl3
How many liters of chlorine
gas are needed to react
with 23.1g aluminum?
23.1 g Al x 1 mole Al x 3 moles Cl2 x 22.4 L Cl2 = 28.7 L Cl2
27.0 g Al
2 moles Al
1 mole Cl2
Fe + O2 a Fe2O3
How many grams of iron (III)
oxide can be produced with
17.2g Fe?
Balance the equation first!!!
4 Fe + 3 O2 a 2 Fe2O3
How many grams of iron (III)
oxide can be produced with
17.2g Fe?
17.2 g Fe x 1 mole Fe x 2 moles Fe2O3 x 159.6 g Fe2O3 = 24.6 g Fe2O3
55.8 g Fe
4 moles Fe
1 mole Fe2O3
4 Fe + 3 O2 a 2 Fe2O3
How many grams of iron
will react with 5.25 liters
of O2 (@STP)?
5.25 L O2 x 1 mole O2 x 4 moles Fe x 55.8 g Fe = 17.4 g Fe
22.4 L O2
3 moles O2
1 mole Fe