1. . 9/26/11 78 Counting Atoms with Coefficients 10/23/2015 77 Counting Atoms with Coefficient 10/23/2015 Starter: QUIZ Application Paste Notes here Connection: Counting Atoms with Coefficients Ws Exit: What is the difference between a carbon dioxide (CO 2) and carbon monoxide (CO)?. Practice: Chemical Formula # of elements# of atoms NaCl CO 2 C 6 H 12 HgOH Ag 2 S Li 2 O EQ: How does the structure of matter explain its properties and the changes it under goes?

2. October 22,2015 AGENDA 8.5 D. I will be able to recognize that chemical formulas identify substances and used to determine the number of atoms of each element in chemical formulas by reading, and writing while completing notes and activity 1 Starter 2. Notes 3. Activity 4. Exit Ca (H 2 PO 4 ) 2 H2OH2O NaCl C2H4O2C2H4O2

3. Table of Contents DateLecture/ Activity/ Lab Page 10/2 Metals, Nonmetals, and Metalliods 53-54 10/5 Comparing Elements Lab 55-56 10/6 Periodic table Graphic Organizer 57-58 10/7 Coloring the periodic table 59-60 10/8 Periodic Puzzles 61-62 10/12 Bohr Model Challenge 63-64 10-13-14 Wheres Al 65-66 10/15 Density 67-68 10/16 Density Lab 69-70 10/19 Molecules, Compounds, and Elements 71-72 10/20 Element and Compound Activity 73-74 10/22 Counting Atoms 75-76 10/23 Counting Atoms with Coefficients 77-78

4. Practice Chemical Formula # of elements# of atoms NaCl CO 2 C 6 H 12 HgOH Ag 2 S Li 2 O 2 22 3 2 18 3 3 2 3 2 3

5. Application: Counting Atoms with Coefficients To determine the number of atoms present, MULTIPLY the subscript by the coefficient

6. Example The coefficient for this compound is 3 3MgCl 2 There are: 1 x 3 = 3 Mg 2 x 3 = 6 Cl

7. “Double” Subscripts Sometimes ions have a “double” subscript 4Al(NO 2 ) 3 One subscript is INSIDE the parenthesis and one subscript is OUTSIDE the parenthesis

8. “ Double” Subscripts To count the number of atoms in a compound with “double” subscripts, you must MULTIPLY the subscripts 4Al 2 (CO 2 ) 3 There are: 2 x 4 = 8 Al atoms 3 x 1 x 4 = 12 C atoms 3 x 2 x 4 = 24 O atoms Total atoms = 44 This “3” applies to both C and O This “2” applies only to the O

9. Example The coefficient for this compound is 5 5Mg(OH) 2 There are: 1 x 5 = 5 Mg 2+ ions 2 x 1 x 5 = 10 O atoms 2 x 1 x 5 = 10 H atoms Total atoms = 25

10. More Examples 1.How many of each atom in Ba 3 (PO 4 ) 2 ? 2.How many of each atom in 4Ba 3 (PO 4 ) 2 ? 3.How many of each atom in Al 2 (Cr 2 O 7 ) 3 ? 4.How many of each atom in 2Al 2 (Cr 2 O 7 ) 3 ?

11. Answers 1.3-Ba, 2-P, 8-0= 13 2.12-Ba, 8-P, 32-O= 52 3.2-Al, 6-Cr, 21-O= 29 4.4-Al, 12-Cr, 42-O= 58

12. . 9/26/11 56 Counting Atoms with Coefficients 10/07/2015 55 Counting Atoms with Coefficient 10/07/2015 Starter: How many atoms are in the following compounds : H 2 O, NaCl, Cl 2 Application Paste Notes here Connection: Counting Atoms with Coefficients Ws Exit: What is the difference between a carbon dioxide (CO 2) and carbon monoxide (CO)?. Practice: Chemical Formula # of elements# of atoms NaCl CO 2 C 6 H 12 HgOH Ag 2 S Li 2 O EQ: How does the structure of matter explain its properties and the changes it under goes?