1. Jump to first page Moles I pledge allegiance to the mole, and to the science from which it comes, one SI unit, extremely divisible, with micromoles and millimoles for all. (Provided by R. Thomas Myers - Kent State University, Kent, OH) I pledge allegiance to the mole, to the International Union of Pure and Applied Chemistry, and to the atomic mass for which it stands, one number, most divisible, with atoms and molecules for all. (Provided by Sylvia Cooper - Morgantown High School, Morgantown, WV

2. Jump to first page Avagadro’s Constant 1 mol = 6.02 x 10 23

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4. Here it is again: one mole of ANY specified entity contains 6.022 x 10 23 of that entity. For example: n One mole of donuts contains 6.022 x 10 23 donuts n One mole of H2O contains 6.022 x 10 23 molecules n One mole of nails contains 6.022 x 10 23 nails n One mole of Fe contains 6.022 x 10 23 atoms n One mole of dogs contains 6.022 x 10 23 dogs n One mole of electrons contains 6.022 x 10 23 electrons

5. Jump to first page What is molar mass ? n The mass in grams of 1 mole of a substance n When we weigh one mole of a substance on a balance, this is called a "molar mass" and has the units g/mol (grams per mole). This idea is very critical because it is used all the time.

6. Jump to first page Conversion factors n Give two conversion factors for the molar masses of the following Na Br 2 Ba(OH) 2 1 mol Na 22.99g Na 22.99g Na 1 mol 1 mol Br 2 159.8g Br 2 159.8g Br 2 1 mol Br 2 1 mol Ba(OH) 2 171.3g Ba(OH) 2 171.3g Ba(OH) 2 1 mol Ba(OH) 2

7. Jump to first page Question ? n How many grams are in 2.5 mol of Na ? 2.5 mol Na x 22.99g Na = 1 mol Na 57.48 g Na

8. Jump to first page Question ? n Convert 0.25 moles of Br 2 to grams.25 mol Br 2 x 159.8 g Br 2 1 mol Br 2 =39.95 g Br 2

9. Jump to first page Question ? n How many moles are in 125 g of Ba(OH) 2 ? 125 g Ba(OH) 2 x 1 mol Ba(OH) 2 1171 g Ba(OH) 2 =.73 mol Ba(OH) 2