Stoichiometry Notes Part II

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Stoichiometry Notes Part II

• Multi-Step Problems

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From yesterday

• Why are mole/mole problems impractical in a
  laboratory setting?

We dont ever measure directly in moles!
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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.

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Al Cl2 a AlCl3

• How many grams of aluminum are needed to produce
  22.7g aluminum chloride?
• Balance the equation first!!!

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2 Al 3 Cl2 a 2 AlCl3

• How many grams of aluminum are needed to produce
  22.7g aluminum chloride?

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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

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Fe O2 a Fe2O3

• How many grams of iron (III) oxide can be
  produced with 17.2g Fe?
• Balance the equation first!!!

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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

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4 Fe 3 O2 a 2 Fe2O3

• How many grams of iron will react with 5.25
  liters of O2 (_at_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