stoichiometry, limiting reagent, yield

1. Chapter 9: Stoichiometry
• Homework: SR on p. 311 (attempt
ALL on LL)
• Anyone who I asked to do a
presentation for the symposium
see me ASAP!!!
• Boards are due by homeroom in
Commons on Friday!
• Like following a recipe
• Key is a balanced equation and
reading the equation in terms of…
• Coefficients
• Let’s examine a few word
problems, starting on p. 305 and
ending on p. 311 after we attempt
one together
Yeaaaaa…
boooyyyy!

2. Let’s try this
Na + Cl  ______
1. Type of reaction?
2. Skeleton equation
3. Balanced equation
4. How is read in terms of
moles?
5. “RECIPE” for moles to
moles, moles to mass,
mass to moles and
mass to mass – what is
the key term here?
6. Examples…

3. Do Now
• Have homework out to
review every single
question!!!
• Boards and binders in
this room! Presentations!
• Write down 1-2 questions
you still have regarding
stoichiometry
• Homework: p. 320, #5-10
on LL
• Collect binders/posters –
presentations in lab!
The pain!
The pain!

4. Do Now
• Quiz – 5 minutes
• Homework: p. 321, #21-27
• Have homework from p. 320 to be collected
• Have questions from homework ready
• Together:
1. What are the ways a balanced equation can be
interpreted?
2. What is a mole ratio?
3. Do you think experiments always work out the way you
planned? Explain…

5. Limiting Reagent
• Once a reactant is used up, there can be no
more products produced
• The substance that is used up first is called the
limiting reagent = the reactant that limits the
amount of the other reactant that can be
combined and thus the product that is produced
• Excess reagent = the substance not used up
completely
• Let’s look at Figure 5 in text; then at Sample
Problem F and G (take notes!!!)

6. Percentage Yield
• Theoretical yield = what you
calculate/expect under perfect conditions
• Actual Yield = what you get in the lab
• Percentage Yield = (AY/TY) x 100%