2. Do Now – April 4(5), 2009 1.What is one thing you did over Spring Break that was different than your normal routine? 2.List three things - any things - that you know about CHEMISTRY!

3. Agenda Do Now/Announcements Review Unit 4 Welcome to Unit 5! Moles! Molar Mass Molecular Weight Exit Ticket

4. Review Make your own Quiz-Quiz-Trade cards Each person will make one card within the topic assigned to your group Use your notes to help you make your question cards Group 1: Parts/Definition Chemical Formulas Group 2: Examples of compounds/formulas Group 3: Characteristics of ionic compounds Group 4: Characteristics of covalent compounds Group 5: How to name ionic/covalent compounds Group 6: Chemical reactions/evidence of reactions

5. Objectives SWBAT describe the mole as a counting unit for tiny particles. SWBAT determine the molar mass of elements. SWBAT calculate the molecular weight of compounds.

6. Happy Mole Day! (After the fact) The mole is so important that it has an entire day dedicated to it. Mole Day is a national celebration observed from 6:02 a.m. to 6:02 p.m. on October 23 rd (10/23) every year

7. The Mole Pledge… 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.

8. More About the Mole We use the mole to count particles Remember that atoms are VERY, VERY small! Since we can’t count individual particles, we use the mole as a counting unit

9. More About the Mole The mole is a unit used to measure the amount of a substance Add to Vocabulary Log!

10. More About the Mole The mole as a unit of measurement is based on the work done almost 200 years ago by Amadeo Avogadro His work led to the association of the number 6.02 x 10 23 with the mole

11. Avogadro’s Number 6.02 x 10 23 is called Avogadro’s Number 6.02 x 10 23 is written in scientific notation 6.02 x 10 23 is equal to… 602,000,000,000,000,000,000,000

12. Avogadro’s Number Avogadro’s Number (aka the mole) is similar to a dozen 1 dozen roses = __?__ roses 1 dozen eggs = __?__ eggs 1 dozen donuts = __?__ donuts 12

13. Avogadro’s Number Avogadro’s Number = 6.02 x 10 23 1 mole eggs = ____?____ eggs 1 mole roses = ____?____ roses 1 mole donuts = ____?____ donuts 1 mole particles = ____?____ particles 6.02 x 10 23

14. How Chemists Use the Mole In lab, chemists will measure out moles of substances Then, they convert the number of moles to number of grams Hey, can I get 3.0 moles of sodium hydroxide please?

15. Molar Mass Molar mass is the mass in grams of one mole of any pure substance Add to Vocabulary Log! The molar mass is of any element is numerically equal to its atomic mass and has the units… grams/mole = g/mol Write down units!

16. Molar Mass In other words…molar mass (molecular weight) is how “heavy” the substance is Units: g/mol = “grams per mole”

17. Molar Mass Remember, the molar mass of any element is numerically equal to its atomic mass (get this off the periodic table!) with the unit g/mol Examples: 1.Manganese = 55.0 g/mol 2.Scandium = 45.0 g/mol 3.Boron = 10.8 g/mol

18. Molar Mass Practice - Your turn! Determine the molar mass of each of the following elements: 1.Tantalum = 2.Phosphorus = 3.Zinc = 4.Lithium = 181.0 g/mol 31.0 g/mol 65.4 g/mol 6.9 g/mol

19. Molecular Weight Molecular weight is the total mass of a compound (or molecule) Add to Vocabulary Log!

20. Steps to Calculate Molecular Weight 1.Count the number of moles (atoms) of each element. 2.Use periodic table to find molar mass of each element 3.Calculate each element’s contribution to the molecular weight. 4.Add up each element’s contribution.

21. Molecular Weight Example 1 Calculate the molecular weight of sodium fluoride - NaF Step 1: 1 mol Na, 1 mol F Step 2: molar mass of… Na = 23.0 g/mol F = 19.00 g/mol Step 3: each element’s contribution to MW 1 x 23.0 g/mol = 24.31 g/mol 1 x 19.00 g/mol = 19.00 g/mol Step 4: 23.0 g/mol + 19.00 g/mol = 42.0 g/mol

22. Molecular Weight Example 2 Calculate the molecular weight of magnesium chloride - MgCl 2 Step 1: 1 mol Mg, 2 mol Cl Step 2: molar mass of… Mg = 24.3 g/mol Cl = 35.5 g/mol Step 3: each element’s contribution to MW 1 x 24.3 g/mol = 24.3 g/mol 2 x 35.5 g/mol = 71.0 g/mol Step 4: 24.3 g/mol + 71.0 g/mol = 95.3 g/mol

23. Molecular Weight Example 3 Calculate the molecular weight of barium nitrate - Ba(NO 3 ) 2 Step 1: 1 mol Ba, 2 mol N, 6 mol O Step 2: molar mass of… Ba = 137.33 g/mol N = 14.01 g/mol O = 16.00 g/mol Step 3: each element’s contribution to MW 1 x 137.33 g/mol = 137.33 g/mol 2 x 14.01 g/mol = 28.02 g/mol 6 x 16.00 g/mol = 96.00 g/mol Step 4: 137.33 g/mol + 28.02 g/mol + 96.00 g/mol = 261.35 g/mol

24. Molecular Weight Practice Your turn! Name the following compounds and calculate the molecular weight of each: 1.H 2 O 2.NaCl 3.CO 2 4.O 3 5.Ca 3 (PO 4 ) 2 18.0 g/mol 59.8 g/mol 44.0 g/mol 48.0 g/mol 310.0 g/mol

25. Wrap-Up of Today’s Learnin! Review What is Mole Day? What is the mole used for? What is Avogadro’s number? What is molar mass? How do you determine the molar mass of an element? What is molecular weight? How do you calculate the molecular weight of a compounds?

26. Exit Ticket 1.What is a mole used for in chemistry? 2.What is the molar mass of oxygen? 3.Calculate the molecular weight of barium hydroxide, Ba(OH) 2.