1. Notes Tennessee SPI Objective: Recognize that in a chemical reaction the mass of the reactants is equal to the mass of the products (Law of Conservation of Mass) Science Essential Learning Students will confirm the Law of Conservation of Mass by examining balanced chemical equations to observe that each side of the equation has the same number and type of atoms. Essential Question(s) How do I determine the number and type of atoms on each side of a chemical equation to confirm the Law of Conservation of Mass? SPI 0807.9.11 Law of Conservation of Mass Instructions 1) First click on "View" from the top-menu bar. 2) Then click on "Slide Show" from the drop-down menu. 3) Then use the right-arrow button on your keyboard to advance through this presentation.

2. Notes Key Points About All Chemical Reactions  No atoms are created or destroyed 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 created or destroyed  Reactants are the "ingredients" and products are what are formed during the reaction Science

3. 5 key Topics You Need to Know  Chemical symbols  Chemical Formulas  Chemical Equations  Subscripts  Coefficients Notes SPI 0807.9.11 Law of Conservation of Mass Science

4. Key Topic Examples:  These are the symbols (letters) that represent the elements from the periodic table  Each element's chemical symbol starts with one capital letter Notes SPI 0807.9.11 Law of Conservation of Mass Science Chemical symbols  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)  Na is a chemical symbol (for the element sodium)

5. Key Topic 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 Example: Put the symbols Na (sodium) and Cl (chlorine) together… …you get the formula for sodium chloride… NaCl Notes SPI 0807.9.11 Law of Conservation of Mass Science Chemical Formulas

6. 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 0807.9.11 Law of Conservation of Mass Science Notes

7. Key Topics CO 2  This small number is called a subscript.  It shows you the number of atoms (2 oxygen atoms)  If there is no subscript present = only one atom  Carbon in this example does not have a subscript. So the capital letter C represents just one atom 2CO  This big number in front is called a coefficient  It tells you to multiply (2 carbon & 2 oxygen atoms) Notes SPI 0807.9.11 Law of Conservation of Mass Science Subscripts and Coefficients

8. Key Topics Five examples that look similar, but are very different 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 Science Chemical symbols and Chemical Formulas Very Important!!!  Pay close attention to the letters and numbers!

9. Key Topics Chemical symbols and Chemical Formulas CO 2 Is this a chemical symbol or a chemical formula? How many total atoms does it contain? Identify the individual atoms. How many carbon atoms? How many oxygen atoms? Quick Review Three Carbon and Oxygen SPI 0807.9.11 Law of Conservation of Mass Science One Two

10. Key Topics Chemical symbols and Chemical Formulas C 6 H 12 O 6 Is this a chemical symbol or a chemical formula? How many total atoms does it contain? Identify the atoms. How many carbon atoms? How many hydrogen atoms? How many oxygen atoms? Quick Review 24 Carbon, hydrogen, and oxygen SPI 0807.9.11 Law of Conservation of Mass Science Six Twelve Six

11. 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 it demonstrate the law of conservation of mass? Four Quick Review Four Two Yes, it most certainly does! SPI 0807.9.11 Law of Conservation of Mass Science