1. 8 th Grade Science Do Now: One molecule of iron oxide has the formula Fe 3 O 4. 1.Iron oxide is made of which elements? 2. How many atoms are in one molecule of iron oxide? 3. How many molecules of iron oxide are shown t the right?

2. 8 th Grade Science Today’s Schedule 1.Do-Now 2.Egg-stracting the Elements 3.Counting Atoms 4.Formula Practice Dry Erase Boards 5.Reflecting on STAAR Dark Matter Objectives: Today we will… 8.5 (D) Recognize that chemical formulas are used to identify substances and determine the number of atoms of each element in chemical formulas containing subscripts. 8.5(F) recognize whether a chemical equation containing coefficients is balanced or not and how that relates to the law of conservation of mass.

3. 8 th Grade Science Work with a partner and use your periodic table to complete the table.

4. 8 th Grade Science H2OH2O Review: How to make a molecule… No Subscript, There is only 1 atom of oxygen in the molecule Subscript Visual modelFormula

5. 8 th Grade Science Count the atoms in each molecule. Record on your answer page. Voice level 2 Time= 15 minutes. Explore: Eggs-tracting the Elements 2 41 H 2 SO 4

6. 8 th Grade Science Write these notes… Law of Conservation of Mass: Matter is not created or destroyed, it just changes forms. In a chemical equation you have the same number and kinds of atoms in the reactants and products. We call this being “balanced”. Example:

7. 8 th Grade Science Explore: Skittles Lab Key Red-Chlorine Orange-Sodium Yellow-Oxygen Green-Hydrogen Blue- Carbon

8. 8 th Grade Science H2OH2O 1 molecule of H 2 O

9. 8 th Grade Science 3 H 2 O 3 molecules of H 2 O

10. 8 th Grade Science Make a table like this in your INB. Explain: Chemical Formulas, page 27 Compound NameChemical FormulaElements/ Number of Atoms Total Number of Atoms

11. 8 th Grade Science

12. The model above is best represented by: a.H 2 O b.2OH c.HOOH d.H 2 O 2

13. 8 th Grade Science The above model shows: a.10 atoms b.2 molecules c.2CH 3 Cl d.All of the above

14. 8 th Grade Science

26. The model above is best represented by: a.H 2 O b.2OH c.HOOH d.H 2 O 2

27. 8 th Grade Science The above model shows: a.10 atoms b.2 molecules c.2CH 3 Cl d.All of the above

28. 8 th Grade Science

34. 6CO 2 + 6H 2 0+ Sun’s light  C 6 H 12 O 6 +6O 2 The above reaction… a.is photosynthesis b.Is respiration c.Transforms radiant energy into chemical energy d.Both a and c.

35. 8 th Grade Science Organic Molecules all contain… a.Sulfur b.Carbon c.Oxygen d.nitrogen

36. 8 th Grade Science All of the following are organic molecules except… a.C 6 H 12 O 6 b.CH 4 c.C 6 H 6 O d.H 2 0

37. 8 th Grade Science

40. Reflecting on STAAR What I know really well… 1. 2. 3. 4. What I still need help with… 1. 2. 3. 4.

41. 8 th Grade Science Today’s Schedule 1.Do-Now 2.Egg-stracting the Elements 3.Counting Atoms 4.Formula Practice Dry Erase Boards 5.Reflecting on STAAR Dark Matter Objectives: Today we will… 8.5 (D) Recognize that chemical formulas are used to identify substances and determine the number of atoms of each element in chemical formulas containing subscripts.

42. 8 th Grade Science Closure: 1.What is the formula for one molecule of iron oxide? 2.How many molecules are shown to the right? 3.How many total atoms are shown to the right? 4.How many atoms in one molecule of iron oxide?