1. STOICHIOMETRY

2. What is stoichiometry? ● quantitative study of a chemical reaction

3. Stoichiometry/mole Ratios A mole ratio converts moles of one compound in a balanced chemical equation into moles of another compound.

4. Example Reaction between magnesium and oxygen to form magnesium oxide. ( fireworks) 2 Mg (s) + O 2(g) 2 MgO(s) Stoichiometry/Mole Ratio: 2 moles : 1 mole:2 moles

5. 1) N 2 + 3 H 2 → 2 NH 3 What stoichiometry/mole ratios exist in this reaction? Practice Problem

6. What You Should Expect Given : Amount of reactants or products Question: how much of something else is formed or needed? Example 2A + 2B 3C Given 20.0 grams of A and lots of B, how many grams of C can be produced?

7. 1) A can of butane lighter fluid contains 1.20 moles of butane (C 4 H 10 ). Calculate the number of moles of carbon dioxide given off when this butane is burned completely. Practice Problems

8. Steps for Stoichiometry Problems 1.Balance the chemical equation 2.Get moles of given compound (may need to use molar mass). 3.Using stoichiometry (mole:mole ratio from balanced reaction), convert from the limiting reagent or product to the desired compound. 4.Using molar mass of the unknown substance, convert moles to mass.

9. Mole-Mole Problems Using the practice question 2) above: Equation of reaction 2C 4 H 10 + 13O 2 8CO 2 + 10H 2 O Mole ratio C 4 H 10 CO 2 1: 4 1.2 : X By factor-label method or cross-multiplication, X = 4.8 mols of CO 2 given off

10. Mole-Mass Problems Problem 2: 1.50 mol of KClO 3 decomposes. How many grams of O 2 will be produced? 2 KClO 3 2 KCl + 3 O 2

11. CHALLENGE 200 60-lb propane tanks explode and burns completely. What volume of the greenhouse gas, CO 2, was produced during this reaction? 1 pound = 0.45359237 kilograms density of CO 2(g) = 1.799 g/L