1. Jan. 12

2. To Do Today Turn in HW Sheet Go over answers Lecture Note Slides: Hand back graded quizzes

3. Relating mass (grams) to Number of atoms Using “The Mole”

4. History of the term “mole” Mole is the English version of the German word "Mol" which is short for Molekulargewicht, the "molecular weight.“ There are claims that it originated as a latin term meaning Mass. Started being used around 1900 Used in textbooks by 1950s Do Not Copy

5. Q: What does Avogadro put in his hot chocolate? Do Not Copy A: Marsh-mole-ows! Q: What did the generous mole say when his friends crashed his party? A: The mole the merrier!

6. Definition of “mole” Amount of a substance that contains as many particles as there are atoms in exactly 12 g of carbon-12. This Amount is 6.02 x 10 23 It is a “counting unit” just as 1 dozen = 12 of anything. 1 mole = 6.02 x 10 23 particles

7. – Chemistry involves vast numbers of atoms. – we need a convenient unit used for counting atoms. – (it takes about 500,000 trillion million carbon atoms to equal just one gram.)

8. – The unit used in Chemistry is the “MOLE”

9. The Mole Info The mole, a fundamental SI unit for "amount of substance," is defined precisely as the number of carbon atoms in 12.01 g of carbon. Do Not Copy

10. The Mole Info It is here that the value of Avogadro's number becomes clear: as noted, carbon has an average atomic mass of 12.01 amu, and multiplication of the average atomic mass by Avogadro's number yields a figure in grams equal to the value of the average atomic mass in atomic mass units. THEREFORE…… Do Not Copy

11. The mass of 1 mole of any element is equal to its atomic mass expressed in grams Atomic masses can be found in the periodic table. – Example: C = 12.01 amu 1 mol C = 12.011 g C

12. – Example: He = 4 amu 1 mol He = 4 g He – Example: N = 14 amu 1 mol N = 14 g N

13. Molar Mass The mass of one mole of a substance is called the molar mass of that substance. Molar mass is written in g/mol

14. Molar Mass The molar mass of an element is equal to the atomic mass of the element. Molar Mass of lithium is 6.94 g/mol Molar Mass of mercury is 200.59 g/mol

15. Relating grams to # of atoms The molar mass of an element contains one mole of atoms. In other words, 1 mole of an element contains 6.02 x 10 23 atoms of the element 1 mole He = 4 grams He = 6.02 x 10 23 atoms of He

16. What is the mass (in grams) of 3.50 mol of copper, Cu? Given: 3.50 mol of Cu Convert between grams and moles using molar mass moles of Cu x (g Cu) = grams Cu moles Cu

17. 3.50 mol Cu x __________ = 222 g Cu 63.55 g Cu 1 mol Cu

18. 3.50 mol Cu x __________ = 222 g Cu 63.55 g Cu 1 mol Cu 3 sig digits

19. What is the mass in grams of 2.25 mol of Fe? 2.25 mol Fe x __________ = 126 g Cu 55.85 g Fe 1 mol Fe 3 sig digits

20. Conversions between grams, moles and # of atoms or molecules gramsmoles # of atoms or molecules molar mass6.02 x 10 23

21. P 219 Monatomic ions Binary ionic compounds Stock system for elements in d block Polyatomic ions Molecular compounds

22. P 237 Formula mass Molar mass Percentage composition Calculation of empirical formulas Calculation of molecular formulas

23. Review equations and reactions Balancing equations P 268 – 9 molar ratios Types of reactions Predicting products

24. Stoichiometry Ch 9

25. Gases Gas law