1. Unit 7 : Stoichiometr y
Stoichiometry
• Any phrase with a Red Underline,
goes in the left column.
• The rest of the information goes in
the right column (even with the
question on the left)
• Text written in Green does not
need to be written.

2. How do we use Moles for calculations?
g g atoms
molecules (mass)
x Subscript
Moles Moles
molecules atoms
molecules atoms

3. What is stoichiometry?
• We’re going on vacation…
2 Shoes + 1 Pants + 1 Shirt

4. What is stoichiometry?
• We’re going on vacation…
6Shoes + 3 Pants + 3 Shirt

5. What is stoichiometry?
• The exact molar quantities that combine in a reaction.
• Based on the Coefficients of a balanced reaction.
3H2 + N2  2NH3
1.5moles 1 moles
6
3 moles .5 moles
2 moles 1
4
2 moles

6. What is stoichiometry?
3H2 + N2  2NH3
.839 moles ? ?
.839 moles H2 1 mole N2
= .280 mole N2
3 moles H2
1. Write down the number and units for the given
2. Same units on the diagonal
3. Units you’re solving for in the numerator
4. For Mole to Mole ratios  Numbers = Coefficients
5. Cancel Units and Solve

7. What is stoichiometry?
3H2 + N2  2NH3
.839 moles .280 moles ?
.839 moles H2 2 moles NH3
= .559 moles 3
mole NH
3 moles H2
1. Write down the number and units for the given
2. Same units on the diagonal
3. Units you’re solving for in the numerator
4. For Mole to Mole ratios  Numbers = Coefficients
5. Cancel Units and Solve

8. What is stoichiometry?
5O2 + P4  2P2O5
3.16 moles ? ?
3.16 moles O2 1 mole P4
= .632 mole P4
moles
5 moles O2
1. Write down the number and units for the given
2. Same units on the diagonal
3. Units you’re solving for in the numerator
4. For Mole to Mole ratios  Numbers = Coefficients
5. Cancel Units and Solve

9. What is stoichiometry?
5O2 + P4  2P2O5
.632moles
3.16 moles .632 ?mole ?
3.16 moles O2 2 moles P2O5
= 1.26 moles P2O5
5 moles O2
1. Write down the number and units for the given
2. Same units on the diagonal
3. Units you’re solving for in the numerator
4. For Mole to Mole ratios  Numbers = Coefficients
5. Cancel Units and Solve

10. What is stoichiometry?
5O2 + P4  2P2O5
Given
(grams) 111 g ? ?
Molar 32 g 124 g 142 g
Mass 1 mole 1 mole 1 mole
S.R.
111 g O2 1 moles O2
= 3.47 moles O2
32 g O2

11. What is stoichiometry?
5O2 + P4  2P2O5
Given
(grams) 111 g ? ?
Molar 32 g 124 g 142 g
Mass 1 mole 1 mole 1 mole
S.R. 3.47 moles
3.47 moles O2 1 moles P4
= .694 moles P4
5 moles O2

12. What is stoichiometry?
5O2 + P4  2P2O5
Given
(grams) 111 g ? ?
Molar 32 g 124 g 142 g
Mass 1 mole 1 mole 1 mole
S.R. 3.47 moles .694 moles
.694 moles P4 124 g P4
= 86.0 g P4
1 moles P4

13. What is stoichiometry?
5O2 + P4  2P2O5
Given
(grams) 111 g ?
86.0 g ?
197 g
Molar
32 g 124 g 142 g
Mass 1 mole 1 mole 1 mole
S.R. 3.47 moles .694 moles 1.39 moles