Notes Science Tennessee SPI Objective: Law of Conservation of Mass Notes Science 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: LOCOM) Essential Question(s) How do I determine the number and type of atoms on each side of a chemical equation to confirm the LOCOM? I Can Statement I can count the numbers of atoms on each side of chemical reactions to confirm LOCOM. Success Criteria I can prove that I understand LOCOM by counting the number of atoms on each side of chemical reactions.

Law of Conservation of Mass Key Points About All Chemical Reactions SPI 0807.9.11 Law of Conservation of Mass Notes Science Key Points About All Chemical Reactions You start with reactants …you end up with products Reactants are the "ingredients" and products are what are formed during the reaction. No atoms are created or destroyed during chemical reactions So no mass is created or destroyed This is called the Law of Conservation of Mass LOCOM

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

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

Law of Conservation of Mass SPI 0807.9.11 Law of Conservation of Mass Notes Science Key Topic Chemical Formulas chemical formulas Chemical symbols combined together = Example: Put the symbols H (hydrogen) and O (oxygen) together… …and you get the formula for water… H2O Example: Put the symbols Na (sodium) and Cl (chlorine) together… …you get the formula for sodium chloride… NaCl

Law of Conservation of Mass SPI 0807.9.11 Law of Conservation of Mass Notes Science Key Topic Chemical Equations Chemical formulas combined together = chemical equations Examples: Equation: 2H2 + O2 2H2O Equation: 2Na + Cl2 2 NaCl

Law of Conservation of Mass Subscripts and Coefficients SPI 0807.9.11 Law of Conservation of Mass Notes Science Key Topics Subscripts and Coefficients CO2 This small number is called a subscript. It tells 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)

Law of Conservation of Mass Chemical symbols and Chemical Formulas SPI 0807.9.11 Law of Conservation of Mass Notes Science Key Topics Chemical symbols and Chemical Formulas Very Important!!! Pay close attention to the letters and numbers! Five examples that look similar, but are very different CO2 = one carbon atom, two oxygen atoms CO = one carbon atom, one oxygen atom Co = one cobalt atom 2CO = two carbon atoms, two oxygen atoms 2CO2 = two carbon atoms, four oxygen atoms

Law of Conservation of Mass Chemical symbols and Chemical Formulas Quick Review SPI 0807.9.11 Law of Conservation of Mass Science Key Topics Chemical symbols and Chemical Formulas CO2 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? Chemical formula Three Carbon and Oxygen One Two

C6H12O6 Key Topics Chemical symbols and Chemical Formulas Science Quick Review SPI 0807.9.11 Law of Conservation of Mass Science Key Topics Chemical symbols and Chemical Formulas C6H12O6 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? Chemical formula 24 Carbon, hydrogen, and oxygen Six Twelve Six

2H2 + O2 2H2O Science Chemical symbols & Chemical Formulas Quick Review SPI 0807.9.11 Law of Conservation of Mass Science Chemical symbols & Chemical Formulas 2H2 + O2 2H2O Is this a chemical formula or a chemical equation? How many hydrogen (H) reactants? How many hydrogen (H) products? How many oxygen (O) reactants? How many oxygen (O) products? Does it demonstrate the law of conservation of mass? chemical equation Four Four Two Two Yes, it most certainly does! (explain why)

2Fe + 3O2 FeO2 Science Chemical symbols & Chemical Formulas Quick Review SPI 0807.9.11 Law of Conservation of Mass Science Chemical symbols & Chemical Formulas 2Fe + 3O2 FeO2 Is this a chemical formula or a chemical equation? How many iron (Fe) reactants? How many iron (Fe) products? How many oxygen (O) reactants? How many oxygen (O) products? Does it demonstrate the law of conservation of mass? chemical equation Two One Six Two No, it does not! (What’s wrong with it?)

2Na + Cl2 2NaCl Science Chemical symbols & Chemical Formulas Quick Review SPI 0807.9.11 Law of Conservation of Mass Science Chemical symbols & Chemical Formulas 2Na + Cl2 2NaCl Is this a chemical formula or a chemical equation? How many sodium (Na) reactants? How many sodium (Na) products? How many chlorine (Cl) reactants? How many chlorine (Cl) products? Does it demonstrate the law of conservation of mass? chemical equation Two Two Two Two Yes, it most certainly does! (explain why)