The document provides an explanation of stoichiometry and how to use mole ratios to solve stoichiometry problems. It defines mole ratios as conversion factors made from the coefficients of a balanced chemical equation. It outlines the steps to solve stoichiometry problems: 1) use a balanced equation, 2) convert quantities to moles if needed, 3) use mole ratios to convert between compounds, and 4) convert back to other units like grams if needed. An example problem is shown calculating moles of products from moles of reactants.

1. Bellwork- Simple Stoich H 2 O 2 (aq)  H 2 O (l) + O 2 (g) 1. Balance the equation 2. How many moles of H 2 O 2 must decompose in order to get 2 moles of O 2 (g)? 3. How many liters of O 2 (g) are formed from the decomposition of 2 moles of H 2 O 2 at STP? 4. Which are conserved in this reaction- Atoms, molecules, volume, moles, mass?

2. If given a quantity for one compound in a balanced equation you can calculate quantities for all of the others using stoichiometry . Example- 2 moles of N 2 requires ____moles of H 2 and will produce ____moles of NH 3. N 2 ( g ) + 3H 2 ( g )  2NH 3 ( g ) Reactant #1 Reactant #2 Product 6 4

3. A mole ratio is a conversion factor made with the coefficients of a balanced chemical equation. N 2 ( g ) + 3H 2 ( g )  2NH 3 ( g )

4. A mole ratio is a conversion factor made with the coefficients of a balanced chemical equation. N 2 ( g ) + 3H 2 ( g )  2NH 3 ( g ) Some mole ratios: 1 mole N 2 3 moles H 2 1 mole N 2 3 moles H 2 1 mole N 2 2 mol NH 3

5. N 2 ( g ) + 3H 2 ( g )  2NH 3 ( g ) Use a mole ratio to convert between two different compounds in a balanced equation! Some mole ratios: 1 mole N 2 3 moles H 2 1 mole N 2 3 moles H 2 1 mole N 2 2 mol NH 3

6. STOICHIOMETRY You need a balanced equation. Convert the given quantity to moles if needed. Convert moles of given compound to moles of another compound by using the mole ratio from the balanced equation. Convert moles to grams if needed N 2 + 3H 2  2NH 3 .6mol N 2 x ________ 1mol N 2 2mol NH 3 = 1.2mol NH 3 These numbers come from the balanced equation

7. for Sample Problem 12.2

8. For Stoichiometry– You ALWAYS use moles!! If you are not given moles you must convert to moles. Use the mole ratio to convert between compounds.

9. 1. How many moles of water are produced when 2.5 mol of O 2 react according to the following equation? C 3 H 8 + 5O 2  3CO 2 + 4H 2 O 2.0 2.5 3.0 4.0