1. Chapter 12 Stoichiometry part 1

2. Stoichiometry The study of quantitative relationships between amounts of reactants used and products formed by a chemical reaction

3. Stoichiometry Calculations of quantities in chemical reactions This means using balanced equations to calculate quantities of chemicals used in a chemical reaction

4. Law of Conservation of Mass Matter is neither created nor destroyed in a chemical reaction Chemical bonds in reactants break and new chemical bonds form to produce products Mass of reactants equals the mass of the products

5. A chemical equation is like a recipe; it shows you how much of each “ingredient” is used and how much product you will have in the end.

6. The heart of stoichiometry is using a balanced chemical equation as a conversion factor for dimensional analysis.

7. N 2 + 3H 2  2NH 3 How many molecules of N 2 are there? How many molecules of H 2 are there? How many molecules of NH 3 are there? So one molecule of N 2 will react with 3 molecules of H 2 to form 2 molecules of NH 3. You could also say that one mole of N 2 will react with 3 moles of H 2 to form 2 moles of NH 3.

8. This equation tells the proportions of N2, H2, and ammonia The coefficients are in a 1:3:2 ratio The ratio could mean molecules or moles of each

9. Review 6.02 x 10 23 particles 1 mole molar mass 1N 2(g) + 3H 2(g)  2NH 3(g)‏ 1 mole 3 moles 2 moles 28.00g 3(2.02)=6.06g 2(14.00+3.03)=34.06g

10. Steps to solve every problem: 1)Write a balanced equation. 2)Put what you have over 1. 3)Convert into moles. 4)Compare using the equation. 5)Convert into the unit the question asks for.

11. Mole to Mass conversion: The mole ratios of the balanced equation is known, and you’re given a quantity in moles, now find the mass of another product or reactant. Mole to Mole conversions: Conversion factor (as with any conversion factor, units must cancel)  Moles of known x moles of unknown = moles unknown Moles of known

12. Burning of propane gas: C3H8(g) + 5O2(g)  3CO2(g) + 4H2O(g) How much oxygen is needed to produce 18 mol of CO2?

13. Zn + HCl  ZnCl 2 + H 2 For the above reaction, how many moles of zinc chloride can be produced with 0.27 moles of zinc? For the above reaction, how many moles of zinc will react with 1.39 moles of hydrochloric acid?

14. Fe + O 2  Fe 2 O 3 How many grams of iron (III) oxide can be produced with 17.2g Fe? How many molecules of O 2 are needed to produce 3.92g Fe 2 O 3 ?

15. Mass to Mass conversion: Again, the mole ratios of the balanced equation is known and you’re given a quantity in grams, now find the mass of another product or reactant. C3H8(g) + 5O2(g)  3CO2(g) + 4H2O(g) 67.02g propane would produce ? grams of water vapor?