2. Day 33 Notes (Chapter 7) Chemical Quantities (The Mole)

3. Amedeo Avogadro Hypothesis: Equal volumes of different gases at the same temperature and pressure contain equal numbers of particles. Amadeo Avogadro H 2 hydrogen CH 4 methane

4. Avogadro’s Number 6.02 x 10 23 is called “Avogadro’s Number” in honor of the Italian chemist Amedeo Avogadro (1776-1855). Amadeo Avogadro I didn’t discover it. Its just named after me!

5. Molar Mass = Mass of 1 mole. Type of compoundUnitsMeaning Ionic Compound (Cation + anion) (metal w/ nonmetals) gfmgram formula mass Molecular Compounds (nonmetal groupings) gmm gram molecular mass Atoms (elements by themselves) gamgram atomic mass Molar Mass (general meaning) g/molgrams/mole

6. The Mole 1 dozen = 1 gross = 1 ream = 1 mole = 12 144 500 6.02 x 10 23 1 mole Carbon = 12.01 g Carbon 6 C 12.01 1 mole Carbon = 6.02 x 10 23 atoms C Molar Mass

7. The mass in grams of 1 mole of a substance. 1 H 1.01 1 mole H = 1.01 g H

8. Calculating Molar Mass Ammonium Chloride + 35.45 g =53.50 g NH 4 Cl 14.01 g x 1 1.01 g x 4 14.01 g+ 4.04 g 35.45 g x 1 7 N 14.01 1 H 1.01 17 Cl 35.45

9. Calculating Molar Mass Aluminum nitrate + 48.00 g) = = 213.01 g Al(NO 3 ) 3 26.98 g x 1 14.01 g x 1 26.98 g (14.01 g 16.00 g x 3 62.01 26.98 g+ 186.03 13 Al 26.98 7 N 14.01 8 O 16.00

10. Alternate method Aluminum nitrate + 144.00 g =213.01 g Al(NO 3 ) 3 26.98 g x 1 14.01 g x 3 26.98 g+ 42.03 g 16.00 g x 9 13 Al 26.98 7 N 14.01 8 O 16.00

11. 20 Ca 40.08 8 O 16.00 1 H 1.01 Calculating Molar Mass Calcium hydroxide = 74.1 g = 74.10 g Ca(OH) 40.08 g x 1 16.00 g 40.08 g + 1.01 g x 2 17.01 40.08 g+ 34.02 2

12. 12 Mg 24.31 15 P 30.97 8 O 16.00 Calculating Molar Mass Magnesium phosphate + 64.00 g) = = 262.87 g Mg 3 (PO 4 ) 2 24.31 g x 3 30.97 g x 1 72.93 g (30.97 g 16.00 g x 4 x 2 94.97 72.93 g+ 189.94

13. 12 Mg 24.31 15 P 30.97 8 O 16.00 Calculating Molar Mass Magnesium phosphate (Alternate Method) + 128.00 g =262.87 g Mg 3 (PO 4 ) 2 24.31 g x 3 30.97 g x 2 72.93 g+ 61.94 g 16.00 g x 8

14. Calculating Molar Mass Dinitrogen tetroxide 92.02 g N2O4N2O4N2O4N2O4 14.01 g x 2 16.00 g x 4 28.02 g+ 64.00 g = 7 N 14.01 8 O 16.00

15. Calculating Molar Mass Phosphorus pentachloride 208.22 g PCl 5 30.97 g x 1 35.45 g x 5 30.97 g+ 177.25 g = 15 P 30.97 17 Cl 35.45

16. Calculating Molar Mass Nitrogen monoxide = 30.01 g NO 14.01 g+ 16.00 g 7 N 14.01 8 O 16.00

17. Calculating Molar Mass Carbon tetrachloride 153.81 g CCl 4 12.01 g x 1 35.45 g x 4 12.01 g+ 141.80 g = 6 C 12.01 17 Cl 35.45

18. Calculating Chemical Quantities Converting from moles to: massvolume representative particles

19. The Mole (Quantities) 1 mole = atoms molecules formula units Molar mass Molar mass (periodic table) 22.4 L for a gas @STP 6.02 x 10 23 (elements) (nonmetals) (cation-anion) Mass: Volume: Representative Particles:

20. 1. Convert 3.00 moles of ammonia, NH 3, to grams of ammonia.

21. 1 mole NH 3 = ?? g NH 3 Conversion factor: 3.00 mol NH 3 x= g NH 3 You have to find molar mass. (Use Periodic Table) mol NH 3 g NH 3

22. 17.04 g NH 3 17.04 g NH 3 NH 3 14.01 g 1.01 g x 3 14.01 g 14.01 g + 3.03 g = x 1 Molar mass of ammonia. 7 N 14.01 1 H 1.01 1 mole NH 3 = 17.04 g NH 3

23. 1. Convert 3.00 moles of ammonia, NH 3, to grams of ammonia. 1 mole NH 3 = 17.04 g NH 3 Conversion factor: 3.00 mol NH 3 x= g NH 3 mol NH 3 g NH 3 NH 3 14.01 1.01 x 1 x 3 14.01 g+ 3.03 g = 17.04 g/mol 117.04 On calculator: 3.00 x 17.04 = 51.12 Round to 3 sig. figs. 51.1 g NH 3

24. Ch. 7 (Calculating Chemical Quantities) 3. 2. 17.04 g NH 3 1 mol NH 3 14.011.01 x 1 x 3 14.01 g + 3.03 g = 17.04 g/mol 1. = 51.1 g NH 3

25. 2.How many molecules of carbon dioxide are in 2.00 moles of CO 2 ?

26. 2.How many molecules of carbon dioxide are in 2.00 moles of CO 2 ? 1 mole CO 2 = 6.02 x 10 23 molecules CO 2 Conversion factor: 2.00 mol CO 2 x= molec. CO 2 1 mole = 6.02 x 10 23 representative particles CO 2 is made of all nonmetals so rep. particles are “molecules” mol CO 2 molec. CO 2

27. 2.How many molecules of carbon dioxide are in 2.00 moles of CO 2 ? 1 mole CO 2 = 6.02 x 10 23 molecules CO 2 Conversion factor: 2.00 mol CO 2 x= molec. CO 2 mol CO 2 molec. CO 2 1 6.02 x 10 23 On calculator: 2.00 x (6.02 x 10 23 ) = 1.204 x 10 24 Round to 3 sig. figs. 1.20 x 10 24 molec. CO 2

28. Ch. 7 (Calculating Chemical Quantities) 3. 1.20 x 10 24 molec. CO 2 2. 17.04 g NH 3 1 mol NH 3 14.011.01 x 1 x 3 14.01 g + 3.03 g = 17.04 g/mol 1. = 51.1 g NH 3

29. 3.How many moles of oxygen are in 44.8 L of oxygen, O 2 ? 1 mole O 2 = 22.4 L O 2 Conversion factor: 44.8 L O 2 x= moles O 2 1 mole = 22.4 L (for any gas @ STP) L O 2 mol O 2 1 22.4 On calculator: 44.8 ÷ 22.4 = 2 Show to 3 sig. figs. 2.00 moles O 2

30. Ch. 7 (Calculating Chemical Quantities) 2.00 mol O 2 3. 1.20 x 10 24 molec. CO 2 2. 17.04 g NH 3 1 mol NH 3 14.011.01 x 1 x 3 14.01 g + 3.03 g = 17.04 g/mol 1. = 51.1 g NH 3

31. 4. How many grams of lithium are in 3.50 moles of lithium? 1 mole Li = g Li Conversion factor: 3.50 mol Li x= g Li mol Li g Li 16.94 On calculator: 3.50 x 6.94 = 24.29 Round to 3 sig. figs. 24.3 g Li

32. 5. How many moles of lithium are in 18.2 grams of lithium? 1 mole Li = g Li Conversion factor: 18.2 g Li x= mol Li g Li mol Li 16.94 On calculator: 18.2 ÷ 6.94 = 2.6225 Round to 3 sig. figs. 2.62 mol Li

33. Representative Particles: Using Avogadro’s Number 6. How many atoms of lithium are in 3.50 moles of lithium? 3.50 mol Li = atoms Li 1 mol Li 6.02 x 10 23 atoms Li 2.11 x 10 24 Use 6.02 x 10 23 when looking for atoms, molecules, or formula units x

34. Representative Particles: Two-part problem 7. How many atoms of lithium are in 18.2 g of lithium? 18.2 g Li = atoms Li 1 mol Li 6.02 x 10 23 atoms Li 1.58 x 10 24 6.94 g Li1 mol Li (18.2)/6.94 x (6.02 x 10 23 ) x x

35. The Mole (Quantities) 1 mole = atoms molecules formula units Molar mass Molar mass (periodic table) 22.4 L for a gas @STP 6.02 x 10 23 (elements) (nonmetals) (cation-anion) Mass: Volume: Representative Particles: