1. Notes Key Points About All Chemical Reactions:  No atoms are lost or gained during chemical reactions SPI 0807.9.11 Law of Conservation of Mass  You start with reactants …you end up with products So no mass is ever lost or gained This is called the Law of Conservation of Mass Press the Right Arrow Button to Advance through the Presentation It should be in "Slide Show" mode. If needed, Click "View" & then "Slide Show"  Reactants are the "ingredients" and products are what you end up with

2. 5 key Topics  Chemical symbols  Chemical Formulas  Chemical Equations  Subscripts  Coefficients Notes SPI 0807.9.11 Law of Conservation of Mass

3. Key Topic Chemical symbols Examples:  H is a chemical symbol (for the element hydrogen)  O is a chemical symbol (for the element oxygen)  Fe is a chemical symbol (for the element iron) Notes SPI 0807.9.11 Law of Conservation of Mass  These are the symbols (letters) about the elements from the periodic table  Each element's chemical symbol starts with one capital letter

4. Key Topic Chemical formulas Chemical symbols combined together = chemical formulas Example: Put the symbols H (hydrogen) and O (oxygen) together… …and you get the formula for water… H 2 O Notes Example: Put the symbols Na (sodium) and Cl (chlorine) together…...and you get the formula for sodium chloride… NaCl SPI 0807.9.11 Law of Conservation of Mass

5. Key Topics Chemical symbols & Chemical Formulas Very Important!!! ss ymbols & formulas must be written correctly! CO 2= one carbon atom, two oxygen atoms CO= one carbon atom, one oxygen atom Co=one cobalt atom 2CO= two carbon atoms, two oxygen atoms 2CO 2 = two carbon atoms, four oxygen atoms Notes SPI 0807.9.11 Law of Conservation of Mass

6. Key Topics Subscripts and Coefficients CO 2  This little number is called a subscript.  It shows you the number of atoms  No subscript present=only one atom 2CO  This big number in front is called a coefficient  It tells you to multiply Notes SPI 0807.9.11 Law of Conservation of Mass

7. Key Topics Chemical symbols & Chemical Formulas CO 2 Is this a chemical symbol or a chemical formula? Is this a mixture or a compound? How many total atoms does it contain? Identify the individual atoms. SPI 0807.9.10 Reactants & Products SPI 0807.9.11 Law of Conservation of Mass Quick Review Three Carbon and Oxygen

8. Key Topic Chemical Equations Chemical formulas combined together = chemical equations Examples: Equation: 2H 2 + O 2 2H 2 O Equation: 2Na + Cl 2 2 NaCl SPI 0807.9.10 Reactants & Products SPI 0807.9.11 Law of Conservation of Mass Notes

9. Key Topics Chemical symbols & Chemical Formulas C 6 H 12 O 6 Is this a chemical symbol or a chemical formula? Is this a mixture or a compound? How many total atoms does it contain? Identify the individual atoms. SPI 0807.9.10 Reactants & Products SPI 0807.9.11 Law of Conservation of Mass 24 Carbon, Hydrogen, & Oxygen Quick Review

10. Key Topics Chemical symbols & Chemical Formulas 2H 2 + O 2 2H 2 O Is this a chemical formula or a chemical equation? How many hydrogen reactants? How many hydrogen products? How many oxygen reactants? How many oxygen products? Does this demonstrate the law of conservation of mass? SPI 0807.9.10 Reactants & Products SPI 0807.9.11 Law of Conservation of Mass Four Quick Review Four Two Yes, it most certainly does!