1. Stoichiometry
Moles to Moles

2. Moles to Moles
Stoichiometry describes the relationships between reactants and products in chemical equations
A balanced chemical equation is the simplest “recipe” for a particular reaction

3. Moles to Moles
CH4 + 3 CuO 3 Cu + 2 H2O + CO
1 molecule of methane reacts with 3 formula units of copper (II) oxide to form 3 atoms of copper, 2 molecules of water, and 1 molecule of carbon monoxide
But this is just the basic recipe. We can multiply the recipe many times if we wish, and the relationship between (ratio) ingredients does not change

4. Moles to Moles CH4 + 3 CuO 3 Cu + 2 H2O + CO 1 molecule 3 units
Basic
1 molecule
3 units
3 atoms
2 molecule

5. Moles to Moles CH4 + 3 CuO 3 Cu + 2 H2O + CO 1 molecule 3 2
Basic
1 molecule 3
units
atoms 2
molecule
x 2
2 molecules 6
4 molecule
2 molecule

6. Moles to Moles CH4 + 3 CuO 3 Cu + 2 H2O + CO 1 3 3 atoms 2 1 molecule
Basic 1
molecule 3
units
3 atoms 2
1 molecule
x 12
12 molecule 36
36 atoms
24 molecule
dozen

7. Moles to Moles 1 mole 3 moles 2 moles 1 molecule 3 3 atoms 2 molecule
CH4 +
3 CuO
3 Cu +
2 H2O + CO
Basic
1 molecule 3
units
3 atoms
2 molecule
x 6.02 x 1023
6.02 x 1023
molecules
1.81 x 1024
atoms
1.20 x 1024 1
mole
3 moles
2 moles

8. Moles to Moles
CH4 + 3 CuO 3 Cu + 2 H2O + CO
Equations usually discussed using number of moles of each chemical involved
(1 mol CH4, 3 mol CuO, 3 mol Cu etc.)
As long as ratios are the same, any amount of reactant can be used with exact same results

9. Moles to Moles
How many moles of aluminum oxide will you produce if you start with 5.40 mol of aluminum?
4 Al + 3 O2 2 Al2O3
Easy to solve: just keep ratios the same!
4 mol Al : 2 mol Al2O3

10. Moles to Moles = 4 Al + 3 O2 2 Al2O3
How many moles of aluminum oxide will you produce if you start with 5.40 mol of aluminum?
4 Al + 3 O2 2 Al2O3
mole ratio
4 mol Al : 2 mol Al2O3
5.40 mol Al
2 mol Al2O3 =
2.7 mol Al2O3
4 mol Al

11. Moles to Moles These problems can ONLY be done using mole ratios
CAN NOT do the same problem using mass ratios
the coefficients in a chemical equation represent molar quantities (numbers of things), not the mass of things

12. Moles to Moles = 4 Al + 3 O2 2 Al2O3
How many moles of oxygen will you need to produce 18 mol of aluminum oxide?
4 Al + 3 O2 2 Al2O3
mole ratio
3 mol O2 : 2 mol Al2O3
18 mol Al2O3
3 mol O2 =
27 mol O2
2 mol Al2O3

13. Start in Class Finish as H.W
PRACTICE PROBLEMS
Start in Class Finish as H.W
In pick-up box

14. Grams to Grams Chemicals used by mass, not by moles
Same problems can be done, just have to covert grams to moles, and then moles back to grams

15. Grams to Grams = 4 Al + 3 O2 2 Al2O3
How many GRAMS of aluminum oxide will you produce if you start with 92 GRAMS of aluminum?
4 Al + 3 O2 2 Al2O3
mole ratio
4 mol Al : 2 mol Al2O3
92 g Al
1 mol Al
2 mol Al2O3
102 g Al2O3 =
g Al2O3
27 g Al
4 mol Al
1 mol Al2O3

16. Grams to Grams = 4 Al + 3 O2 2 Al2O3
How many GRAMS of oxygen will you need to produce 219 GRAMS of aluminum oxide?
4 Al + 3 O2 2 Al2O3
mole ratio
3 mol O2 : 2 mol Al2O3
219 g Al2O3
1 mol Al2O3
32 g O2
3 mol O2 =
103.1 g O2
102 g Al2O3
2 mol Al2O3
1 mol O2

17. GRAMS #1
GRAMS #2
MOLES #2
MOLES #1
MOLE:RATIO