1. New page in journal 1/16/13 10.1 The Mole Add to TOC On your 3x5 Card –name above top line –number the next 6 lines 1 through 6

2. 1.How many is a pair? 2.How many is a dozen? 3.How many is a score? 4.How many is a gross? 5.How much is a bushel? 6.How many is a ream?

3. 1.pair = 2 2.dozen = 12 3.score = 20 4.gross = 144 (12 dozen) 5.bushel = 4 pecks or 8 gallons (dry volume) 6.ream = 500

4. The Mole But not this kind

6. Open to back of book – Periodic Table One atom of hydrogen has an atomic mass of 1.00794 –1.00794 amu (atomic mass unit) Oxygen?

7. So, a molecule of H 2 O has a formula mass of 18.00988 amu –18.0099 due to significant figures H: 2 x 1.00794 2.01588 amu O: 1 x 15.999415.9994_ amu 18.00988 amu

8. In science, a mole is a unit of measurement –we use it like pair and dozen –symbol (abbreviation): mol

9. A mole stands for 6.02 x 10 23 particles of a substance –we call this Avogadro’s number –based on the number of atoms in 12.0 grams of carbon-12 –in chemistry, 6.02 x 10 23 atoms Example: 1 mole of iron equals 6.02 x 10 23 atoms of iron

10. Why do chemists use moles? Moles make it easier to measure and count small particles Does a dozen eggs have a different mass than a dozen grapefruit? Yes! Does a mole of carbon have a different mass than a mole of silicon? Yes

11. The atomic mass of an element is its molar mass How many grams in 1 mole of hydrogen? 1.0079 grams

12. How many grams in 1 mole of NaCl Na = 22.990 grams per mole Cl = 35.453 grams per mole 22.990 g + 35.453 g = 58.443 grams of NaCl per mole of NaCl

13. How do you convert between grams and moles? Dimensional Analysis

14. You have 55.0 grams of CO 2 How many moles of CO 2 do you have?

15. First you need your conversion factor –How many grams of CO 2 are in 1 mole of CO 2 C = 12.011 grams per mole O = 15.999 grams per mole –and we need 2 of these 12.011 g + (2 x 15.999 g) = 44.009 g/mol

16. Balancing Equations WS #1 due today WS #2 due before weekend Your 5 Balancing Equations problems due before weekend Mole-Mass Conversions Worksheet #1 due Wednesday of next week –we will spend lots of time in class working these problems