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Catalyst: Happy Wednesday!. Which quantity is larger? 4.5 x 10 34 or 6.5 x 10 20 2.3 x 10 -3 or 4.5 x 10 -6 5000 or 5 x 10 5 HW Due: Read textbook pp. 224-229 Do problems: pp. 233 #1, 2, 4, 5, 6(a), 8(a) Tonight’s HW: Read textbook pp. 230, 236-240 pp. 233 #6(b, c, d), 7(c), 8(b )
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Catalyst: Happy Wednesday! Which quantity is larger? • 4.5 x 1034 or 6.5 x 1020 • 2.3 x 10-3 or 4.5 x 10-6 • 5000 or 5 x 105 • HW Due: Read textbook pp. 224-229 • Do problems: pp. 233 #1, 2, 4, 5, 6(a), 8(a) • Tonight’s HW: Read textbook pp. 230, 236-240 • pp. 233 #6(b, c, d), 7(c), 8(b) • Valence electron review worksheet!
Lesson Objective I will be able to explain what a “mole” in chemistry means!
Agenda • Catalyst • HW Review • Intro to Molar Conversions Worksheet • Exit Slip
HW: pp. 233 #1, 2, 4, 5, 6(a), 8(a) 1. A mole is the number of atoms in exactly 12 g of carbon-12. 2. There are 6.022 x 1023 particles in one mole. “Particles” refers to atoms, ions, or molecules. • 1 mol of nickel(II) and 1 mol of nickel(III) both contain exactly 6.022 x 1023 ions. • (This is like asking “which is heavier: 1 pound of feathers or a 1 pound brick?” They are both 1 pound! Similarly, 1 mol of anything always contains 6.022 x 1023 of whatever is being counted.) • 1.11 mol Pt is more than 6.022 x 1023 atoms. • (This is the same as asking whether 1.11 is more or less that 1.00 because 1.00 mol = 6.022 x 1023 particles. 1.11 is more than 1.00.)
HW Review Continued… • 6(a). 1.204 x 1024 ions Fe3+ • 8(a). 0.500 mol H2O • We will work through how to answer these questions in today’s lesson!
Focus Questions Today • What is a mole, besides a small mammal or a growth on your body, and what is it good for, besides digging holes? • Do all moles weigh the same amount?
Analogy: Think of the term dozen... How many doughnuts are in a dozen? How many eggs are in a dozen? How many bricks are in a dozen? How many ostriches are in a dozen?
Counting By Weighing • Atoms and molecules are too small to see • We measure out atoms by using a number called the mole!!!!
What is the mole? (Notes) • A mole is the number of atoms in 12 grams of carbon-12. • There are 6.022 x 1023 atoms in 12 grams of carbon-12. • 1 mole (mol) = 6.022 x 1023 particles.
A mole is very similar to a dozen. But instead of meaning 12 of something, it means 6.02 x 1023 of something. 6.02 x 1023 = 602,000,000,000,000,000,000,000 Or Six hundred and two sextillion!
1 mole (mol) = 6.02 x 1023 This number is a constant. The number of particles in 1 mole is called Avogadro’s Number!
6.02 x 1023 Avocado Avogadro
So one mole of... ...doughnuts is 6.02 x 1023 doughnuts ... Ostriches is 6.02 x 1023 ostriches ...oxygen atoms is 6.02 x 1023 atoms of oxygen (O) ...oxygen molecules is 6.02 x 1023 molecules of oxygen (O2)
Review- The mole - MEMORIZE • 1 mole = 6.02 x 1023 particles • 6.02 x 1023 is called Avogadro’s number • The periodic table is based on the molar mass of carbon (C)
THE MOLE -- Why? • Why is the mole useful to us as chemists?? • Make a dot on your paper with your pencil. • Guess how many atoms of Carbon graphite are in that dot. • 25 million atoms in that tiny dot!
Say it! • How many particles are in 1 mole? • 6.02 x 1023 • How many atoms are in 1 mole of carbon? • How many atoms are in 1 mole of sodium? • How many atoms are in 1 mole of helium? • How many ducks are in 1 mole of ducks?
Conversions MOLES particles
How many particlesare in 1 mole of something? 6.02 x 1023 To convert from number of moles to number of particles, multiply the number of moles by the conversion factor: 6.022 x 1023 1 mol
Example 1: • How many particles are in 2.00 moles? • Multiply 2.00 mol x 6.022 x 1023 particles = 12.04 x 1023 1.00 mol
How many particlesare in 1 mole of something? 6.02 x 1023 To convert from number of particles to number of moles, multiply the number of moles by the conversion factor: 1 mol___ 6.022 x 1023
Example 2: • How many moles is 3.01 x 1022 atoms? • Multiply (3.01 x 1022atoms) x __1.00 mole = 0.5 x 10-1 mole 6.022 x 1023 atoms Scientific notation… 0.5 x 10-1 mole = 5.0 x 10-2 mole
Agenda • Catalyst • HW Review • Intro to Molar Conversions Worksheet • Exit Slip
Exit Slip • Draw the Lewis Dot structure for the molecule: HBr • How many molecules of HBr are in 2.00 mole of HBr? • Which has more atoms: A mole Platinum or a mole of tin?
Random Mole Facts! • Since the Earth has a radius of about 6400 km, its volume is approximately 1021 m3. Since about 500 large grapefruit will fit in one cubic meter, it therefore follows that a mole of grapefruit would have approximately the same volume as the Earth. • If you had exactly one mole of sheets of paper, you could make one million equal stacks from sea level on the earth that would pass the sun. • If you had a mole of pennies, you could give out enough money to everyone in the world so that they could spend a million dollars every hour, day and night, for the rest of their lives.