A New Unit of Measurement A Chemistry Exclusive!!!

Atoms are REALLY small!!! We can ’ t work with individual atoms or atomic mass units in the LAB – Because we can ’ t see things that small We work with samples large enough for us to SEE and WEIGH on a balance using units of grams.

This Creates a Problem … A pile of atoms big enough for us to see contains billions of atoms. – Billions of atoms are hard to keep track of in calculations

So chemists made up a new unit

What ’ s a MOLE? It ’ s a number of things – Just like a dozen 1 dozen eggs = 12 eggs 1 mole eggs = x eggs

Pop Quiz 1 dozen Mg atoms =12 Mg atoms 1 mole Mg atoms =6.022 x Mg atoms 1 mole Mg(OH)2 = x Mg(OH)2 molecules 1 mole O2 =6.022 x O2 molecules

Everybody Dance Now!!! Moleshake My moleshake brings all the moles to the yard, And they're like, "Man, Chemistry's hard" Yeah right, yeah Chemistry's hard, I can teach you, and I won't even charge

How Big is a Mole? A mole of marbles would cover the entire Earth ’ s surface 50 MILES DEEP!!!!

How Big is a Mole? If you spent a BILLION DOLLARS every SECOND, you couldn ’ t spend a mole of dollar bills in your lifetime!!!

How Big is a Mole? If you were able to count at the rate of 1 million numbers a second, it would take about 20 billion years to count out one mole.

Avogadro ’ s Number 1 mole = x particles, molecules, atoms x is referred to as Avogadro ’ s Number – In honor of Amedeo Avogadro, Italian chemist ( ) x is often symbolized as “ N A ”

The Mole Song

Moles to Particles Calculations

There are 268 donuts. How many dozens are present? N = number = 268 donuts D = ? Dozens N D = 12 donuts per dozen D = N = 268 donuts = dozens There are 22 dozens of donuts N D NDND __ _______________ N D 12 donuts/dozen

There are 2.46 x donuts. How many moles are present? N = number = 2.46 x n = moles = ? N A = Avogadro’s number = 6.02 x n = N = 2.46x donuts = mol There are 4.09 mol of donuts NANA N n __ ________________ N A 6.02 x donuts/mol

There are 0.50 mol of methane, CH 4 in a flask. How many molecules are present? n = 0.50 mol N A = 6.02 x molecules/mol N = molecules =? N = n x N A = (0.50 mol)(6.02 x molecules/mol) = 3.01 x molecules There are 3.0 x molecules of methane

In the same sample of methane, determine how many atoms of H are present In 1 molecule of CH 4, there are 4 hydrogen atoms 4 hydrogen = x x = 1.20 x atoms of H *Note* Covalent compounds are composed of molecules. Ionic compounds are composed of formula units ______________ ____________________ 1 molecule CH x molecules

How many molecules are found in 1.25 mol of CO 2 ? n = 1.25 mol N A = 6.02 x molecules/mol N = molecules =? N = n x N A = (1.25 mol)(6.02 x molecules/mol) = x molecules There are 7.52 x molecules of carbon dioxide

How many atoms are found in 2.25 mol of CO 2 ? n = 2.25 mol N A = 6.02 x molecules/mol N = molecules =? N = n x N A = (2.25 mol)(6.02 x molecules/mol) = x molecules x X 3 atoms = 4.06 x atoms 1 molecule

How many moles are found in 5.83 x molecules of CO 2 ? n = ? N A = 6.02 x molecules/mol N = 5.83 x molecules n = N/N A = 5.83 x molecules / 6.02 x molecules n = 9.68 mol

How many moles of lithium oxide are there if you have 1.75 x Li atoms?