Stoichiometry The Mole - Study Questions   1.       What were Avogadro’s 2 major contributions to chemistry? 2.       What is the unit for mass used on the periodic table? 3.       How does molecular mass differ from molar mass? 4.       Convert 200 g of FeO to moles. 5.       Convert 3 mol of CO2 to grams. 6.       What is a conversion factor? 7.       If 25 g of a substance equals 1 mole, what conversion factor would you use to convert 1.5 mol to grams? 8.       What conversion factor would be used to convert 3 mol of the substance in question 10 to grams? 9.       What is the unit used for molecular and formula mass? 10.     What is the unit of molar mass? 11.     The oxidation of 50.0 g of Mn produces 79.1 g of an oxide. Calculate (a) the percent composition, and (b) the empirical formula of this oxide. 12.     What two things are conserved in a chemical reaction? 13.     Why aren’t moles conserved in a chemical reaction? For the next 4 questions balance the equation and calculate the indicated quantity. 14.       K(s) + H2O (g)  KOH(aq) + H2(g) How much KOH will be produced from 100 g of K? 15.       Fe2O3(s) + C  Fe(l) + CO(g) How much CO will be produced from 100 g of C? 16.       CaC2(s) + H2O(l)  Ca(OH)2(s) + CsH2(g) How much CaC2 is required to produce 100 g of C2H2? 17.       C4H10(g) + O2  CO2(g) + H2O(l) How much H2O can be produced using 100 g O2? 18.     What is a mole? 19.     How many particles are there in a mole?

Mole Map Mass Mountain Liter Lake Mole Island Particle Peninsula

Using the Mole Map with Chemical Equations We can convert between Moles, Particles and Grams, but… This only gives us information about one substance! How do we determine how much reactants to use in a chemical reaction? Or how much product we will create? STOICHIOMETRY

Proportional Relationships 2 1/4 c. flour 1 tsp. baking soda 1 tsp. salt 1 c. butter 3/4 c. sugar 3/4 c. brown sugar 1 tsp vanilla extract 2 eggs 2 c. chocolate chips Makes 5 dozen cookies. I have 5 eggs. How many cookies can I make? Ratio of eggs to cookies 5 eggs 5 doz. 2 eggs = 12.5 dozen cookies 150 cookies Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem

Mole Ratio A conversion factor that converts moles of one compound in a balanced chemical equation into moles of another compound. 2 H2 + O2  2 H2O Coefficients tell how many particles (or MOLES of particles) of each chemical is needed in the reaction.

Mole Ratios How many moles of water will be formed if I react 14.0 moles of oxygen with excess H2? 2 H2 + O2  2 H2O 14.0 moles O2 x 2 moles H2O = 28.0 moles H2O 1 mole O2 MOLE RATIO From the balanced equation. Coefficients tell moles of each substance.

Stoichiometry Sea Known Unknown Substance A Substance B Mole Ratio Mass Mountain Mass Mountain Liter Lake Liter Lake Mole Ratio Raft Mole Island Mole Island Particle Peninsula Particle Peninsula

Known Substance A Unknown Substance B Mass Mass 1 mole = molar mass (g) 1 mole = molar mass (g) Mole Volume Use coefficients from balanced chemical equation Mole 1 mole = 22.4 L @ STP 1 mole = 22.4 L @ STP Volume 1 mole = 6.022 x 1023 particles (atoms or molecules) 1 mole = 6.022 x 1023 particles (atoms or molecules) Particles Particles

Stoichiometry Steps Core step in all stoichiometry problems!! 1. Write a balanced equation. 2. Identify known & unknown. 3. Line up conversion factors. Mole ratio - moles  moles Molar mass - moles  grams Mole ratio - moles  moles 4. Check answer. Core step in all stoichiometry problems!! Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem

How many moles of KClO3 must decompose in order to produce 9 moles of oxygen gas? 2KClO3  2KCl + 3O2 ? mol 9 mol 2 mol KClO3 x mol KClO3 = 9 mol O2 6 mol = 6 mol KClO3 3 mol O2 O2 KClO3 Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem

Stoichiometry 2 TiO2 + 4 Cl2 + 3 C CO2 + 2 CO + 2 TiCl4 115 g x g x mol 4.55 mol x molecules How many moles of chlorine will react with 4.55 moles of carbon? 4 mol Cl2 x mol Cl2 = 4.55 mol C = 6.07 mol Cl2 3 mol C C Cl2 How many grams of titanium (IV) oxide will react with 4.55 moles of carbon? 2 mol TiO2 80 g TiO2 x g TiO2 = 4.55 mol C = 243 g TiO2 3 mol C 1 mol TiO2 C TiO2 How many molecules of TiCl4 will react with 115 g TiO2? 1 mol TiO2 2 mol TiCl4 6.02x1023 molecules TiCl4 x molecules TiCl4 = 115 g TiO2 80 g TiO2 2 mol TiO2 1 mol TiCl4 = 8.66x1023 molecules TiCl4 TiO2 TiCl4