Welcome to STOICHIOMETRY

Chocolate Chip Cookies 2.25 cups flour 8 Tbsp butter 0.5 cups shortening 0.75 cups sugar 0.75 cups brown sugar 1 tsp salt 1 tsp baking soda 1 tsp vanilla 0.5 cups Egg Beaters

Chocolate Chip Cookies 2.25 cups flour 8 Tbsp butter 0.5 cups shortening 0.75 cups sugar 0.75 cups brown sugar 1 tsp salt 1 tsp baking soda 1 tsp vanilla 0.5 cups Egg Beaters How much? What units? Of what?

2.25 cups flour + 8 Tbsp butter cups shortening cups sugar cups brown sugar + 1 tsp salt + 1 tsp baking soda + 1 tsp vanilla cups Egg Beaters (a synthesis reaction) (177ºC) 1 batch of chocolate chip cookies! coefficient unit substance

2.25 cups flour 8 Tbsp butter 0.5 cups shortening 0.75 cups sugar 0.75 cups brown sugar 1 tsp salt 1 tsp baking soda 1 tsp vanilla 0.5 cups Egg Beaters For 1 batch: The Egg Beaters I have are close to expiring! I’d like to use the rest of them in this recipe. I have 1.5 cups of Egg Beaters. How many batches of cookies can I make with that many Egg Beaters?

Let’s Revisit the Cookies… 2.25 cups flour 8 Tbsp butter 0.5 cups shortening 0.75 cups sugar 0.75 cups brown sugar 1 tsp salt 1 tsp baking soda 1 tsp vanilla 0.5 cups Egg Beaters For 1 batch: I have 1.5 cups of Egg Beaters. How many batches of cookies can I make with that many Egg Beaters? = 3.0 batches of cookies 1.5 cups E.B..5 cups E.B. 1 Batch

What is Stoichiometry? The study of quantitative relationships within chemical reactions A balanced equation is the key to stoichiometry! Tools you’ll need for this chapter:  Writing proper formulas and balanced reactions  Converting from mass to moles and vice versa

Determining the Mole-Ratio Mole-Ratio  Indicated by the coefficients in a balanced equation What is the mole-ratio between Mg and MgO? 2 mol Mg 2 mol MgO 2 Mg + O 2  2 MgO

Examples of Mole-Ratios 2KClO 3  2KCl + 3O 2 What is the mole-ratio of KClO 3 and KCl? 2 moles KClO 3 2 moles KCl What is the mole-ratio of KClO 3 and O 2 ? 2 moles KClO 3 3 moles O 2

Another Example Cu + 2AgNO 3  2Ag + Cu(NO 3 ) 2 What is the mole ratio for silver nitrate and silver? 2 moles AgNO 3 2 moles Ag What is the mole ratio for copper and silver nitrate? 1 mole of Cu 2 moles of AgNO 3

Conversion Chart Molar Mass (g/mol) 6.02  particles/mol MASS IN GRAMS MOLES NUMBER OF PARTICLES LITERS OF SOLUTION Molarity (mol/L) The Mole-Mole Ratio is the core step!!

Stoichiometric Calculations There are three types of stoichiometry problems we will deal with today:  Mole-Mole problems  Mass-Mole problems  Mass-Mass problems

Step 1: Write a BALANCED EQUATION Step 2: Determine known & unknowns Step 3: Set up the mole ratio from the coefficients in the equation. Step 4: Set up the problem like a unit conversion and solve! Mole-Mole Problems

Example: 2 H 2 + O 2 2 H 2 O How many moles of water can be formed from 0.5 mol H 2 ? = 0.5 mol H 2 O.5 mol H 2 2 mol H 2 2 mol H 2 O

Mole-Mole Practice CuSO 4 AlAl 2 (SO 4 ) 3 Cu mol Al3 mol CuSO 4 2 mol Al =0.75 mol CuSO 4 Mole ratio How many moles of CuSO 4 are required to react with.5 moles of Al? How many moles of Al 2 (SO 4 ) 3 are produced from.5 moles of Al? 0.5 mol Al1 mol Al 2 (SO 4 ) 3 2 mol Al =.25 mol Al 2 (SO 4 ) 3 Mole ratio

Mole-Mole Practice 2.5 mol Ca 2 mol AlCl 3 3 mol Ca = 1.7 mol AlCl mol Ca 3 mol CaCl 2 3 mol Ca = 2.5 mol CaCl 2 CaAlCl 3 CaCl 2 Al How many moles of AlCl 3 are required to react with 2.5 moles of Ca? How many moles of CaCl 2 are produced from 2.5 moles of Ca?

Mass-Mole Problems Step 1: Write a BALANCED EQUATION Step 2: Determine your known & unknowns Step 3: Convert known mass to moles (molar mass-known) Step 4: Convert known mole to unknown mole (Mole-Mole ratio)

Mass-Mole Problems Example: 2 H 2 + O 2 2 H 2 O How many moles of water can be formed from 48.0 g O 2 ? 48.0 g O 2 1 mol O 2 2 mol H 2 O = 3.00 mol H 2 O g O 2 1 mol O 2

Mass-Mole Practice CuSO 4 AlAl 2 (SO 4 ) 3 Cu g Al 1 mol Al g Al = mol CuSO g Al 1 mol Al 2 (SO 4 ) 3 2 mol Al = mol Al 2 (SO 4 ) 3 Mole ratio 3 mol CuSO 4 2 mol Al 1 mol Al g Al How many moles of CuSO 4 are required to react with 13.5 g of Al? How many moles of Al 2 (SO 4 ) 3 are produced when 13.5g of Al react?

Mass-Mole Practice 5.7 g Ca 2 mol AlCl 3 3 mol Ca = mol AlCl g Ca 3 mol CaCl 2 3 mol Ca = 0.14 mol CaCl 2 CaAlCl 3 CaCl 2 Al mol Ca g Ca 1 mol Ca g Ca 3 How many moles of AlCl 3 are required to react with 5.7g of Ca? How many moles of CaCl 2 are produced when 5.7g of Ca react?

Mass-Mass Problems Step 1: Write a BALANCED EQUATION Step 2: Determine your known & unknowns Step 3: Convert known mass to moles (molar mass- known) Step 4: Convert known mole to unknown mole (Mole- Mole ratio) Step 5: Convert unknown mole to gram (molar mass- unknown)

Mass-Mass Problems Example: 2 H 2 + O 2 2 H 2 O How many grams of water can be formed from 48.0 g O 2 ? 48.0 g O 2 1 mol O 2 2 mol H 2 O = g O 2 1 mol O g H 2 O 1 mol H 2 O 54.1 g H 2 O

Mass-Mass Practice CuSO 4 AlAl 2 (SO 4 ) 3 Cu g Al 1 mol Al g Al = 75 g CuSO g Al 1 mol Al 2 (SO 4 ) 3 2 mol Al = 54 g Al 2 (SO 4 ) 3 Mole ratio 3 mol CuSO 4 2 mol Al 1 mol Al g Al 1 mol CuSO g Al 2 (SO 4 ) 3 1 mol Al 2 (SO 4 ) g CuSO 4 How many grams of CuSO4 are required to react with 8.5g Al? How many grams of Al 2 (SO 4 ) 3 are produced when 8.5g Al react?

Mass-Mass Practice 1.9 g Ca 2 mol AlCl 3 3 mol Ca = 4.2 g AlCl g Ca 3 mol CaCl 2 3 mol Ca = 5.3 g CaCl 2 CaAlCl 3 CaCl 2 Al mol Ca g Ca 1 mol Ca g Ca g AlCl 3 1 mol AlCl 3 1 mol CaCl g CaCl 2 3 What mass of AlCl 3 is required to react with 1.9g of Ca? What mass of CaCl 2 is produced when 1.9g of Ca react?