1. . 9/26/11 62 Counting Atoms 10/15/2013 61 Counting Atoms 10/15/2013 Starter: How many elements are in the following compounds : H2O, NaCl, Cl2 Application How many atoms 1. 2. 3. 4. 5. Connection: Counting Atoms Ws Exit: How does a chemical formula help us know what atoms are in a compound? Explain in 2-3 complete sentences. Practice: SubscriptCoefficients 1. 2. 3. example

2. October 15, 2013 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. DateLecture/ Activity/ Lab Page 9/25 Metal, Nonmetals, and Metalloids 41-42 9/26 Where’s Al? 43-44 9/27 Element Wanted Poster 45-46 9/30 Bohr Model Challenge 47-48 10/1 Periodic Table Notes/Puzzles 49-50 10/2 Periodic Table Chart 51-52 10/3 Test Review 53-54 10/8 Test Corrections 55-56 10/9 Molecules, Compounds, and Elements 57-58 10/10 Build a Molecule Activity 59-60 10/15 Counting Atoms 61-62 Table of Contents

4. Coefficients and Subscripts 6H 2 O + 6CO 2 C 6 H 12 O 6 + 6O 2 Water + Carbon Dioxide Sugar + Oxygen

5. Why Do We Use Chemical Formulas and Equations? Scientists use equations to show: how a chemical reaction took place what elements were involved what was produced from the reaction

6. Subscripts small numbers behind the element symbol Show how atoms of an element there are. 6H 2 O + 6CO 2 C 6 H 12 O 6 + 6O 2 2 hydrogen atoms 6 carbon atoms

7. Subscripts Subscripts show the number of atoms H2H2 H4H4 H3H3

8. Coefficients are added to the front of a formula show how many molecules of the compound there are 6H 2 O + 6CO 2 C 6 H 12 O 6 + 6O 2 6 water molecules 6 Oxygen molecules

9. Coefficients Coefficients show the number of molecules. 4H 2 O 2H 2 O 3H 2 O

10. How Many Atoms? NaCl Fe 2 O 3 2 1 sodium 1 chlorine 5 2 Iron 3 oxygen

11. How Many Atoms? H 3 PO 4 NaC 2 H 3 O 3 3 hydrogen 1 phosphorus 4 oxygen 8 1 sodium 2 carbon 3 hydrogen 3 oxygen 9

12. How Many Atoms? (CH 3 ) 2 CO 3 Carbon 6 Hydrogen 1 Oxygen 10

13. Add on back of sheet H 2 SO 4 Ca(PO 4 ) 2 HCl CaCO 3 C 2 H 4 O 2

14. . 9/26/11 62 Counting Atoms 10/15/2013 61 Counting Atoms 10/15/2013 Starter: How many elements are in the following compounds : H2O, NaCl, Cl2 Application How many atoms 1. 2. 3. 4. 5. Connection: Counting Atoms Ws Exit: How does a chemical formula help us know what atoms are in a compound? Explain in 2-3 complete sentences. Practice: SubscriptCoefficients 1. 2. 3. example