The document discusses stoichiometry and using mole ratios to calculate amounts of substances in a chemical reaction. It provides an example of using the mole ratio from a balanced chemical equation between iron (III) oxide and aluminum to calculate how many moles of aluminum are needed to fully react with a given amount of iron (III) oxide. It also works through an example of using a mole ratio to calculate the grams of sodium hydroxide needed to fully react with 3.10 grams of sulfuric acid based on the balanced equation. Mole ratios allow conversion between amounts of any two substances involved in a chemical reaction.

1. ENGAGE

2. Aluminum metal reacts with iron (II) oxide powder to
produce aluminum oxide solid and iron metal.
Write and balance the chemical equation:
2𝐴𝑙(𝑠) + 3Fe𝑂(𝑠) 𝐴𝑙2𝑂3 + 3Fe

3. A balanced chemical equation shows what reactants combine to
form what products .It also shows the numerical relationships
between the reactants and products

4. It also shows the numerical relationships between
the reactants and products
STOICHIOMETRY

5. A common type of stoichiometric relationship is
the mole ratio, which relates the amounts in moles
of any two substances in a chemical reaction.
Balanced equations and mole ratios

6. We can write a mole ratio for a pair of substances by
looking at the coefficients in front of each species in
the balanced chemical equation.
Balanced equations and mole ratios

7. EXAMPLE:
𝐹𝑒2𝑂3 + 2𝐴𝑙2 2Fe + 𝐴𝑙2𝑂3
Using this ratio, we could calculate how many Al moles end are
needed to fully react with a certain amount of 𝐹𝑒2𝑂3, or vice
versa. In general, mole ratios can be used to convert between
amounts of any two substances involved in a chemical reaction.

8. Using mole ratios to calculate mass of a reactant
Consider the following unbalanced equation:
NaOH+𝐻2𝑆𝑂4→𝐻2𝑂+𝑁𝑎2𝑆𝑂4
How many grams of NaOH are required to fully consume 3.10 grams
of 𝐻2𝑆𝑂4

9. SOLUTION
1.Balance the chemical equation.
2NaOH+𝐻2𝑆𝑂4→2𝐻2𝑂+𝑁𝑎2𝑆𝑂4

10. SOLUTION
2NaOH+𝐻2𝑆𝑂4→2𝐻2𝑂+𝑁𝑎2𝑆𝑂4
Step 2: Convert known reactant mass to moles
In order to relate the amounts 𝐻2𝑆𝑂4 and NaOH, using a mole ratio we
first need to know the quantity of 𝐻2𝑆𝑂4 in moles. We can convert
the 3.10 grams of 𝐻2𝑆𝑂4 to moles using the molar mass
of 𝐻2𝑆𝑂4 (98.08 g/mol):

11. SOLUTION
2NaOH+𝐻2𝑆𝑂4→2𝐻2𝑂+𝑁𝑎2𝑆𝑂4
Step 3: Use the mole ratio to find moles of other reactant

12. SHORTCUT SOLUTION
Be sure to pay extra close attention to the units if you take this approach, though!

13. ACTIVITY