1. Bellwork Wednesday Dig around in your brain and fill in the following…
1 mole = ___________________ atoms
1 mole = ___________________ liters
1 mole = ___________________ g H2O
3 mole = ________________ molecules

2. CHEMISTRY Unit 8 CHAPTER 12
Stoichiometry

3. Just What is a Chemical Ratio?
A mole ratio is like making a s’more.
The “chemical reaction for a s’more would be…
3 chocolate squares + 1 marshmallow graham crackers  1 s’more
If you want to make 3 s’mores, how many marshmallows would you need?
3 s’mores = 3 marshmallows
If you have 27 chocolate squares, how many smores can you make?
3 chocolate squares = 1 s’more so 27 chocolate squares = 9 s’mores

5. 12.1
Stoichiometry – study of calculations of quantities in chemical reactions using balanced chemical equations.
2Mg + O2  2MgO
2 moles Mg + 1mole O2  2 moles MgO

6. 2Mg + O2  2MgO
The mole ratios can be obtained from the coefficients in the balanced chemical equation.
What are the mole ratios in this problem?
Mole ratios can be used as conversion factors to predict the amount of any reactant or product involved in a reaction if the amount of another reactant and/or product is known.

7. Mole Ratio! What’s that mean?
Well, a stoichiometry problem gives you an amount of one chemical and asks you to solve for a different chemical.
To get from one type of chemical to another, a MOLE RATIO must be found between the two chemicals. You get the MOLE RATIO from the BALANCED CHEMICAL EQUATION!

8. The mole map Always follow the road map… Do not make up new paths!
R.P. of substance given
R.P. of substance wanted
Coefficients in a balanced equation!
Atoms, formula units, molecules
6.02 x 1023
1mol
Atoms, formula units, molecules
6.02 x 1023
1mol
Mass of substance given
Moles of substance given
Moles of substance wanted
Mass of substance wanted
gfm
1mol
gfm
1mol
grams
mol
mol
grams
22.4 L
1mol
22.4 L
1mol
Always follow the road map… Do not make up new paths!
Volume of substance given
Volume of substance wanted
L, mL
L, mL

9. *the coefficients are*
A balanced chemical equation tells the quantity of reactants and products as well as what they are.
2 mol mol mol
*the coefficients are*
Mole Ratios

10. The MOLE RATIO is the bridge between the two different chemicals
The MOLE RATIO is your mechanism of transition between the chemical that is your starting given and the chemical you are solving for.
The MOLE RATIO is the bridge between the two different chemicals
moles
moles
(given)
(want)
Mole
Ratio
? want
given

11. 12.2
Mole - Mole Calculations – Mole ratios are used to calculate the number of moles of product from the given number of moles of reactant, or vice versa.
Lets get back to those s’mores. If you have the following reaction…
3 chocolate squares + 1 marshmallow graham crackers  1 s’more
You have 325 chocolate squares and you want to make the maximum number of s’mores possible. Show a calculation for this reaction.
325 c.s. 1 s’more = or 108 s’mores
3 c.s.

12. EXAMPLE
Calculate the number of moles of Na2O that will be produced when 5.00 moles of Na completely react with oxygen gas.
4Na + O2  2Na2O
5.00 mol Na
2 mol Na2O =
2.50 mol Na2O
4 mol Na
mol-mol ratio

13. Mole-Mass Calculations:
We use mole ratios from balanced chemical equations and the molar conversions from Ch. 7 to calculate amounts (grams) of substances needed or produced in chemical reactions.

14. EXAMPLE mol-mol ratio GFM
How many grams of KClO3 must decompose to produce KCl and 1.45 moles O2?
2KClO3 → 2KCl + 3O2
1.45 moles O2
2 mol KClO3
122.6 g KClO3 =
3 mol O2
1 mol KClO3
119 g KClO3
mol-mol ratio
GFM

15. Mass-Mass Calculations:
Same as mole-mass calculations, with an additional step of converting mass to moles.

16. EXAMPLE GFM mol-mol ratio GFM
When 24.0 g of Na are mixed with Cl2, are 52.0 g of NaCl produced? Explain. 2
Na + Cl2 → NaCl 2
1 mol Na
2 mol NaCl
58.5 g NaCl
24.0 g Na =
23.0 g Na
2 mol Na
1 mol NaCl
GFM
mol-mol ratio
GFM
61.0 g NaCl
Are 52.0 g produced?
Actually more than 52.0 g were produced.

17. CaCO3, limestone, is heated to produce calcium oxide, CaO, and CO2
CaCO3, limestone, is heated to produce calcium oxide, CaO, and CO2. What mass of limestone is required to produce g of CaO?
CaCO3 (s)  CaO (s) + CO2 (g)
156.0 g CaO
1 mol CaO
1 mol CaCO3
100.1 g CaCO3
56.1 g CaO
1 mol CaO
1 mol CaCO3
GFM
mol-mol ratio
GFM
278.4 g CaCo3 =

18. I will take up the lab in a moment
Summary part 1 p.139

19. Bellwork Thursday
Magnesium metal reacts with oxygen in a synthesis reaction. Write and balance the equation, then fill in the chart concerning the particles and mass.
Total Particles of Reactants 
Total Particles of Products
Total Moles of Reactants
Total Moles of Products
Total Mass of Reactants
Total mass of Products