1. Page 1 of 11 What is Stoichiometry? 12.1

2. Page 2 of 11 What is Stoichiometry? 12.1 You will write mole ratios from balanced chemical equations. What You’ll Learn In Chapter 12 You will calculate the # of moles & the mass of a reactant or product when given the # of moles or the mass of another reactant or product. You will identify the limiting reactant in a chemical reaction. You will determine the percent yield of a chemical reaction.

3. Page 3 of 11 What is Stoichiometry? 12.1 Objectives of Chapter 12.1 Identify the quantitative relationships in a balanced chemical equation. Determine the mole ratios from a balanced chemical equation.

4. Page 4 of 11 What is Stoichiometry? 12.1 Comes from the Greek words “stoicheion”, meaning “element”, and “metron”, meaning “measure”. Stoichiometry

5. Page 5 of 11 What is Stoichiometry? 12.1 Using methods of stoichiometry, we can measure & relate amounts of substances involved in chemical reactions. Stoichiometry For example, a sample’s mass or volume can be converted to a count of the # of its particles, such as atoms, ions, or molecules. The study of quantitative relationships between amounts of reactants used & products formed by a chemical reaction is called stoichiometry.

6. Page 6 of 11 What is Stoichiometry? 12.1 Methanol is formed from CO 2 gas & hydrogen gas according to the balanced chemical equation below. Mole-Mass Relationships Suppose you wanted to produce 500 g of methanol.

7. Page 7 of 11 What is Stoichiometry? 12.1 How many grams of CO 2 gas & H 2 gas would you need? How many grams of water would be produced as a by-product? Those are questions about the masses of reactants & products. But the balanced chemical equation shows that 3 molecules of hydrogen gas react w/ 1 molecule of carbon dioxide gas. Mole-Mass Relationships

8. Page 8 of 11 What is Stoichiometry? 12.1 Like Avogadro, you need to relate the macroscopic measurements-the masses of carbon dioxide & hydrogen-to the # of molecules of methanol. To find the mass of carbon dioxide & the mass of hydrogen needed to produce 500 g of methanol, you 1 st need to know how many molecules of methanol are in 500 g of methanol. The equation relates molecules, not masses, of reactants & products. Mole-Mass Relationships

9. Page 9 of 11 What is Stoichiometry? 12.1 Mole-Mass Relationships A mole ratio is a ratio between the # of moles of any 2 substances in a balanced chemical equation. How many mole ratios can you identify in this chemical equation?

10. Page 10 of 11 What is Stoichiometry? 12.1 Do 3 Problems

11. Page 11 of 11 What is Stoichiometry? 12.1 Objectives of Chapter 12.1 Identify the quantitative relationships in a balanced chemical equation. Determine the mole ratios from a balanced chemical equation.