Slide 1

Please take out your periodic table, your notebook and a calculator. Slide 2 H Chem. Fall 2012 Slide 3 Pair = 2 Dozen = 12 Half = 0.5 Bakers Dozen = 13 Gross = 144 Mole = 6.02 x 10 23 Slide 4 One mole = 6.02 x 10 23 = 602,000,000,000,000,000,000,000 of bananas, monkeys, stars, anything. Slide 5 How many atoms are in 4.2 moles of carbon? 4.2 moles C x 6.02 x 10 23 atoms C = 2.5 x 10 24 atoms C 1 mole C How many atoms are in 4.2 moles of magnesium? 4.2 moles Mg x 6.02 x 10 23 atoms Mg = 2.5 x 10 24 atoms Mg 1 mole Mg Slide 6 One mole of anything always has 6.02 x 10 23 items in it. Slide 7 Notice when we ask how many it is like asking how many baseballs are in 4.5 dozen and how many basketballs are in 4.5 dozen? It is the same number. The mole allows us to count numbers. It is also helpful to find massbecause the mass listed on the periodic table tells us how much mass 1 mole of each element has. (different for every element just like 4.5 dozen baseballs does not have the same mass as 4.5 dozen basketballs.) Slide 8 Atomic mass and molar mass are very similar Atomic MassMolar Mass The mass of one atomThe Mass of 1mole of atoms Unit- amugrams Carbon Atomic Mass= 12.01 amuMolar Mass =12.01 grams Magnesium Atomic Mass = 24.31 amuMolar Mass 24.31 grams Slide 9 To find the mass of one mole of any element check the periodic table. To find the mass of one mole of any compound add the masses of each element in the compound. Slide 10 What is the molar mass of Sodium? 22.99 g/mol How many Sodium atoms are in one mole? 6.02 x 10 23 atoms What is the molar mass of Zinc? 65.39 g/mol How many Zinc atoms are in one mole? 6.02 x 10 23 atoms Slide 11 Example: What is the molar mass of water? 18.02 g/mol How Many Molecules of water are in a mole? 6.02 x 10 23 molecules Slide 12 You try it: What is the molar mass of CO 2 ? 44.01 g/mol How many molecules are in 1 mole of CO 2 ? 6.02 x 10 23 molecules Slide 13 What would the mass of 3 moles of carbon be? 3 moles C x 12.01 grams C = 36.03 grams C 1 mole C 12.01 grams/mole is the molar mass of C Slide 14 We can also go from mass to moles: (use unit analysis to show your work) How many moles of Ca in 100. grams of calcium? How many atoms is that? Slide 15 You try it: How many moles of Mg in 96 grams of magnesium? How many atoms is that? Slide 16 How many atoms are in 24.8 g of carbon? How many molecules are in 42.7 g of water?