1. Chapter 5 Chemical Quantities and Reactions 5.1 The Mole 1

2. Collection Terms A collection term states a specific number of items. 1 dozen donuts = 12 donuts 1 ream of paper = 500 sheets 1 case = 24 cans 2

3. A Mole of Atoms A mole is a collection that contains the same number of particles as there are carbon atoms in 12.0 g of carbon. 6.02 x 10 23 atoms of an element (Avogadro’s number). 1 mole element Number of Atoms 1 mole C = 6.02 x 10 23 C atoms 1 mole Na = 6.02 x 10 23 Na atoms 1 mole Au= 6.02 x 10 23 Au atoms 3

4. A Mole of a Compound A mole of a covalent compound has Avogadro’s number of molecules. 1 mole CO 2 = 6.02 x 10 23 CO 2 molecules 1 mole H 2 O = 6.02 x 10 23 H 2 O molecules of an ionic compound contains Avogadro’s number of formula units. 1 mole NaCl = 6.02 x 10 23 NaCl formula units 1 mole K 2 SO 4 = 6.02 x 10 23 K 2 SO 4 formula units 4

5. Samples of 1 Mole Quantities 1 mole of S atoms= 6.02 x 10 23 S atoms 1 mole of H 2 O molecules= 6.02 x 10 23 H 2 O molecules 5

6. Avogadro’s Number Avogadro’s number, 6.02 x 10 23, can be written as an equality and two conversion factors. Equality: 1 mole = 6.02 x 10 23 particles Conversion Factors: 6.02 x 10 23 particles and 1 mole 1 mole 6.02 x 10 23 particles 6

7. Using Avogadro’s Number Avogadro’s number is used to o convert moles to particles o convert particles to moles 7

8. Converting Moles to Particles Avogadro’s number is used to convert moles of a substance to particles. How many Cu atoms are in 0.50 mole of Cu? 8

9. Converting Particles to Moles Avogadro’s number is used to convert particles of a substance to moles. How many moles of CO 2 are in 2.50 x 10 24 molecules CO 2 ? 9

10. Examples 1. The number of atoms in 2.0 mole of Al atoms is A. 2.0 Al atoms. B. 3.0 x 10 23 Al atoms. C. 1.2 x 10 24 Al atoms. 2. The number of moles of S in 1.8 x 10 24 atoms of S is A. 1.0 mole of S atoms. B. 3.0 moles of S atoms. C. 1.1 x 10 48 moles of S atoms. 10

11. Subscripts and Moles The subscripts in a formula show the relationship of atoms in the formula. the moles of each element in 1 mole of compound. Glucose C 6 H 12 O 6 In 1 molecule: 6 atoms C 12 atoms H6 atoms O In 1 mole: 6 moles C 12 moles H 6 moles O 12

12. Subscripts State Atoms and Moles 9 moles of C 8 moles of H 4 moles of O 13

13. Factors from Subscripts The subscripts are used to write conversion factors for moles of each element in 1 mole of a compound. For aspirin, C 9 H 8 O 4, the possible conversion factors are: 9 moles C 8 moles H 4 moles O 1 mole C 9 H 8 O 4 1 mole C 9 H 8 O 4 1 mole C 9 H 8 O 4 and 1 mole C 9 H 8 O 4 1 mole C 9 H 8 O 4 1 mole C 9 H 8 O 4 9 moles C 8 moles H 4 moles O 14

14. Examples A. How many moles of O are in 0.150 mole of aspirin, C 9 H 8 O 4 ? B. How many atoms of O are in 0.150 mole of aspirin, C 9 H 8 O 4 ? 15

15. Chapter 5 Chemical Quantities and Reactions 5.2 Molar Mass 15

16. Molar Mass The molar mass is the mass of 1 mole of an element or compound. is the atomic or molecular mass expressed in grams. 16

17. Molar Mass from Periodic Table Molar mass is the atomic mass expressed in grams. 17 1 mole of Ag 1 mole of C 1 mole of S = 107.9 g = 12.01 g = 32.07 g

18. Examples Give the molar mass for each (to the tenths decimal place). A. 1 mole of Mg atoms =________ B. 1 mole of Ag atoms =________ 18

19. Guide to Calculation Molar Mass of a Compound 19

20. Molar Mass of a Compound The molar mass of a compound is the sum of the molar masses of the elements in the formula. Example: Calculate the molar mass of MgCl 2. 20 ElementNumber of Moles Atomic MassTotal Mass Mg Cl MgCl 2

21. Molar Mass of K 3 PO 4 Calculate the molar mass of Na 3 PO 4. 21 ElementNumber of Moles Atomic MassTotal Mass in K 3 PO 4 Na P O Na 3 PO 4

22. Some 1-mole Quantities 32.1 g 55.9 g 58.5 g 294.2 g 342.2 g 22 One-Mole Quantities

23. Example Prozac, C 17 H 18 F 3 NO, is an antidepressant that inhibits the uptake of serotonin by the brain. What is the molar mass of Prozac? 1) 40.1 g/mole 2) 262 g/mole 3) 309 g/mole 23

24. Molar Mass Factors Molar mass conversion factors are fractions (ratios) written from the molar mass. relate grams and moles of an element or compound. for methane, CH 4, used in gas stoves and gas heaters is 1 mole of CH 4 = 16.0 g (molar mass equality) Conversion factors: 16.0 g CH 4 and 1 mole CH 4 1 mole CH 4 16.0 g CH 4 24

25. Example Acetic acid, C 2 H 4 O 2, gives the sour taste to vinegar. Write two molar mass conversion factors for acetic acid. 25

26. Calculations Using Molar Mass Molar mass factors are used to convert between the grams of a substance and the number of moles. 26 Grams Molar mass factor Moles

27. Moles to Grams Aluminum is often used to build lightweight bicycle frames. How many grams of Al are in 3.00 mole of Al? Molar mass equality: Setup with molar mass as a factor: 27

28. Learning Check Allyl sulfide, C 6 H 10 S, is a compound that has the odor of garlic. How many moles of C 6 H 10 S are in 225 g? 28

29. Grams, Moles, and Particles A molar mass factor and Avogadro’s number convert… 29

30. Examples How many H 2 O molecules are in 24.0 g of H 2 O? 1) 4.52 x 10 23 H 2 O molecules 2) 1.44 x 10 25 H 2 O molecules 3) 8.03 x 10 23 H 2 O molecules 30

31. Examples How many water molecules are in 3.26 g of water? How many H atoms are in 3.26 g of water? 31