1. Stoichiometry Chapter 9 Mole-to-mole ratios Stoich ppt _1 mole-mole

2. Stoichiometry After this presentation, you should understand:  Moles, mass, representative particles (atoms, molecules, formula units), molar mass, and Avogadro’s number.  Calculations using balanced chemical equations: for example, for a given number of moles of a reactant, calculate the amount of moles of product formed.

3. Proportional Relationships I have 5 eggs. How many cookies can I make? 3/4 c. brown sugar 1 tsp vanilla extract 2 eggs 2 c. chocolate chips Makes 5 dozen cookies. 2 1/4 c. flour 1 tsp. baking soda 1 tsp. salt 1 c. butter 3/4 c. sugar 5 eggs5 doz. 2 eggs = 12.5 dozen cookies (150 cookies!) Ratio of eggs to cookies

4. Proportional Relationships Stoichiometry – mass relationships between substances in a chemical reaction – based on the mole ratio Mole Ratio – indicated by coefficients in a balanced equation 2 Mg + O 2  2 MgO

5. Stoichiometry Steps 1. Write a balanced equation. 2. Identify known & unknown. 3. Line up conversion factors. – Mole ratio - moles  moles – Molar mass -moles  grams – Molar volume -moles  liters gas This is the new one –from the balanced equation. The key step in stoichiometry! 4. Check answer, units, significant figures.

6. Mass, Volume, Mole Relationship

7. Molar Mass (g/mol) 6.02  10 23 particles/mol MASS IN GRAMS MOLES NUMBER OF PARTICLES Molar Volume (22.4 L/mol) LITERS OF GAS AT STP

8. Welcome to Mole Island 1 mole = 22.4 L @ STP 1 mol = molar mass 1 mol = 6.02 x 10 23 particles

9. Stoichiometry Island Diagram Mass Particles VolumeMole Mass Known Unknown Substance A Substance B Stoichiometry Island Diagram Volume Particles M V P Mass Mountain Liter Lagoon Particle Place Mole Island

10. Stoichiometry Island Diagram Mass Particles Volume Mole Mass Volume Particles Known Unknown Substance A Substance B Stoichiometry Island Diagram 1 mole = molar mass (g) Use coefficients from balanced chemical equation 1 mole = 22.4 L @ STP 1 mole = 6.022 x 10 23 particles (atoms or molecules) 1 mole = 22.4 L @ STP 1 mole = 6.022 x 10 23 particles (atoms or molecules) 1 mole = molar mass (g) (gases)

11. Time to Practice! Grab your calculator and periodic table.

12. How many moles of KClO 3 must decompose in order to produce 9 moles of oxygen gas? 9 mol O 2 2 mol KClO 3 3 mol O 2 = 6 mol KClO 3 2KClO 3  2KCl + 3O 2 ? mol9 mol O2O2 KClO 3 ? mol KClO 3 = 9 mol O 2 = 6 mol KClO 3 2 mol KClO 3 3 mol O 2 6 mol

13. How many moles of O 2 can be produced when 12 moles of KClO 3 decompose? 12 mol KClO 3 3 mol O 2 2 mol KClO 3 = 18 mol O 2 2KClO 3  2KCl + 3O 2 12 mol? mol O2O2 KClO 3 ? mol O 2 = 12 mol KClO 3 = 18 mol O 2 3 mol O 2 2 mol KClO 3

14. How many moles of O 2 can be produced when 8 moles of KCl are formed? 8 mol KCl 3 mol O 2 2 mol KCl = 12 mol O 2 2KClO 3  2KCl + 3O 2 8 mol? mol O2O2 KClO 3 ? mol O 2 = 8 mol KCl = 12 mol O 2 3 mol O 2 2 mol KCl 12 mol