Mole Triangle Review Begin Stoichiometry Chemistry GT 3/5/15

Drill How many moles are equivalent to: 450. g Ca(OH)2 935.2 g zinc chloride HW: Mole-Mole/Mass-Mass WS (finish)

Objectives IWBAT Convert from moles to grams and back Convert from moles to units and back Convert from moles to liters and back Use the mole triangle to do two step conversions

Mole Triangle We can convert between Ms. Bloedorn will show you how!  Mol  g and back mol  particle and back mol  L and back Ms. Bloedorn will show you how! 

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

What’s going on here? The candle burns freely in air, but what happens when it is covered with a beaker? smothered, goes out What fuel runs out first? oxygen runs out

Mole Chemical Relationships Mole-Mass Relationships in Chemical Reactions: Law of Conservation of Mass: Mass cannot be created or destroyed by ordinary chemical changes Look at: Fe(s) + O2(g)  Fe2O3(s) Is it balanced? If not, balance it. 4 Fe(s) + 3 O2(g)  2 Fe2O3(s)

Interpret the equation Iron + oxygen  Iron (III) oxide 4Fe(s) + 3O2(g)  2Fe2O3(s) 4 atoms Fe + 3 molecules O2  2 molecules Fe2O3 4 mol Fe + 3 mol O2  2 mol Fe2O3 223.4 g Fe + 96.00 g O2  319.4 g Fe2O3 These all tell you different information, but also represent the same reaction.

Stoichiometric Calculations 1/2 cup butter 1/2 cup brown sugar 1/2 cup granulated sugar 1 egg 1/2 teaspoon vanilla 1 cup all-purpose flour 1/2 teaspoon salt 1/2 teaspoon baking soda 1/2 cup semisweet chocolate chips Makes 42 cookies. What is the product of this chemical reaction? 42 cookies How would you adjust the ingredients to make seven dozen cookies? Make twice as much (7 x 6, then 7 x 12)

The Mole “Bridge” moles of B moles of A Moles of A Moles of B # grams B 1 mol B 1 mol A # grams A Grams of A Grams of B *** You MUST have a balanced equation! ***

Stoichiometry Conversion Flowchart wA + xB  yC + zD Liters A Liters B 22.4L B 1 mol B 1 mol B 22.4L B 22.4L A 1 mol A 1 mol A 22.4L A 1 mol B 6.022 x 1023 units B 6.022 x 1023 units A 1 mol A w mol A x mol B Atoms/ units B Atoms/ units A mol B mol A 1 mol A 6.022 x 1023 units A x mol B w mol A 1 mol B Molar mass B 6.022 x 1023 units B 1 mol B Molar mass g B 1 mol B 1 mol A Molar mass A Molar mass g A 1 mol A grams A grams B

Stoich. Calculations, cont. Sometimes, a chemist needs to make a certain amount of a product, or only has a certain amount of a starting material. How much reactant should be used? How much product will be made? ex. How many moles of hydrogen will be produced when 0.0400 mol potassium react with water? 2K(s) + 2H2O(l)  2KOH(aq) + H2(g) 0.0400 mol K • 1 mol H2 = 0.0200 mol H2 2 mol K

Mass to Mass Conversion Ammonium nitrate (NH4NO3) decomposes into N2O and water. Determine the mass of water produced from the decomposition of 25.0 g solid ammonium nitrate. NH4NO3  N2O + 2H2O 25.0 g NH4NO3 • 1 mol NH4NO3 • 2 mol H2O • 18.02 g H2O = 11.3 g H2O 80.04 g NH4NO3 1 mol NH4NO3 1 mol H2O

Practice Start on Mole-Mole side of WS Then, Mass-Mass side of WS

Closure Calculate, in 2.3 mol Na3PO4, How many grams?