180 likes | 343 Views
Stoichiometry & the Mole. What is stoichiometry?. How many whos are the same as 12 mabees? (1 who = 5 mabees) 12 mabees x 1 who = 2.4 who 1 5 mabees. Practice. 1 whosits = 3 whatever 211 whosits = 12.5 farts 75 farmvilles = 1 no sleep 110 mafia wars = 2 no sleeps
E N D
What is stoichiometry? • How many whos are the same as 12 mabees? (1 who = 5 mabees) • 12 mabees x 1 who = 2.4 who • 1 5 mabees
Practice 1 whosits = 3 whatever 211 whosits = 12.5 farts 75 farmvilles = 1 no sleep 110 mafia wars = 2 no sleeps 6.02 whosits = 1 mole 20 farts = 1 ROFL 1 mole = 2.5 mice
Questions • How many farmvilles equal 4 no sleeps? • How many farts in 367 whosits? • How many mice in 12.04 whosits? • How many moles equal 15 ROFL?
Answers • 300 farmvilles • 21.7 farts • 5.000 mice • 840 moles
The Mole Conversion Factor 6.02 x 1023 units = 1 mole Ex 6.02 x 1023 pencils = 1 mole of pencils Ex. 12 eggs = 1 dozen eggs Ex. 6.02 x 1023 thumb tacks = 1 mole thumb tacks
Dimensional Analysis Review • How many seconds are in 5.0 hours? • 5.0 hr • 5.0 hr x 60 min x 60 sec = 18000 sec 1 hr 1 min
Stoichiometry • Stoichiometry is just a long word for changing units in chemistry • If you can do Dimensional Analysis, you can do stoichiometry
The Mole • Chemists need a convenient method for counting accurately the number of atoms, molecules, or formula units in a sample of a substance. • The mole, commonly abbreviated mol, is the SI base unit used to measure the amount of a substance.
The Mole • A mole of anything contains 6.0221367 x 1023 representative particles. • A representative particle is any kind of particle such as atoms, molecules, formula units, electrons, or ions. • In this class, Avogadro’s number will be rounded to three significant figures— 6.02 x 1023.
Mole – Representative Particle Calculations • Calculate the number of atoms in 3.50 moles of copper • Start with your given • 3.50 mol Cu • Draw your line • 3.50 mol Cu x _________
Mole – Representative Particle Calculations • Place the conversion factors • 3.50 mol Cu x 6.02 x 1023 atoms 1 mol • Work the problem • 2.11 x 10 24 atoms Cu
Mole – Representative Particle Calculations • How many moles of MgO are in 9.72 x 10 23 molecules of MgO? • 1.61 mol MgO
Stoichiometry • Using the methods of stoichiometry, we can measure the amounts of substances involved in chemical reactions and relate them to one another.
Conversion Factor # 3 # Moles A # Moles B The #’s in front of A & B MUST come from the balanced chemical equation
Mole – Mole Relationship • 4 Fe + 3O2 2Fe2O3 • 4 mol Fe / 3 mol O2 • 4 mol Fe / 2 mol Fe2O3 • 3mol O2 / 2 mol Fe2O3 • If we have 8 moles of Fe, we will produce 4 moles of Fe2O3.
Mole – Mole Relationship • 4 Fe + 3O2 2Fe2O3 • How many moles of Fe2O3 can we form from 5.0 mol of Fe? • 5.0 mole Fe x 2 mol Fe2O3 4 mol Fe • 2.5 mol Fe2O3