Chapter 7 SPI Reactants & Products SPI Law of Conservation of Mass Bellwork 1  Turn to page 340, and read the 3 rd paragraph about reactants and products. 1) Contrast reactants and products (how are they different?) 2) Look at the formula below. Identify the reactants and products C + O 2 CO 2

Chapter 7 SPI Reactants & Products SPI Law of Conservation of Mass Bellwork 1 1)Contrast reactants and products (how are they different?) Reactants-starting materials in a chemical reactions  Always written before the arrow C + O 2 CO 2

Chapter 7 SPI Reactants & Products SPI Law of Conservation of Mass Bellwork 1 1)Contrast reactants and products (how are they different?) Reactants-starting materials in a chemical reactions Products-substances formed in a chemical reaction  Always written after the arrow C + O 2 CO 2

Chapter 7 SPI Reactants & Products SPI Law of Conservation of Mass 3 key Topics  Chemical symbols  Chemical Formulas  Chemical Equations Notes

Chapter 7 SPI Reactants & Products SPI Law of Conservation of Mass Key Topics Chemical symbols Notes Examples: H is just a chemical symbol (for the element hydrogen) O is just a chemical symbol (for the element oxygen)

Chapter 7 SPI Reactants & Products SPI Law of Conservation of Mass Key Topics Chemical formulas Notes Chemical symbols combined together = chemical formulas Examples: Put the symbols H and O together… And you get the formula for water… H 2 O

Chapter 7 SPI Reactants & Products SPI Law of Conservation of Mass Key Topics Chemical symbols & Chemical Formulas Notes Very Important!!!  symbols & 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

Chapter 7 SPI Reactants & Products SPI Law of Conservation of Mass Key Topics Chemical symbols & Chemical Formulas Notes QUICK REVIEW! CO 2 Is this a chem symbol or chem formula? Is this a mixture or a compound? How many total atoms does it contain? Identify the individual atoms.

Chapter 7 SPI Reactants & Products SPI Law of Conservation of Mass Key Topics Chemical symbols & Chemical Formulas Notes Nov 5, 2012 QUICK REVIEW! CO 2 Is this a chem symbol or chem formula? It is a chemical formula

Chapter 7 SPI Reactants & Products SPI Law of Conservation of Mass Key Topics Chemical symbols & Chemical Formulas Notes QUICK REVIEW! CO 2 Is this a mixture or a compound? It is a compound

Chapter 7 SPI Reactants & Products SPI Law of Conservation of Mass Key Topics Chemical symbols & Chemical Formulas Notes QUICK REVIEW! CO 2 How many total atoms does it contain? Three

Chapter 7 SPI Reactants & Products SPI Law of Conservation of Mass Key Topics Chemical symbols & Chemical Formulas Notes QUICK REVIEW! CO 2 Identify the individual atoms. = one carbon atom, two oxygen atoms

Chapter 7 SPI Reactants & Products SPI Law of Conservation of Mass Key Topics Chemical Equations Notes Chemical formulas combined together = chemical equations Examples: Equation: 2H 2 + O 2 2H 2 O Equation: 2Na + Cl 2 2 NaCl

Chapter 7 SPI Reactants & Products SPI Law of Conservation of Mass 2 parts of chemical equations  (1) reactants  (2) products Reactants: are the things you are combing together…the things you start with in a chemical reaction Products: are the things that you produce in a chemical reaction… the things you end up with Example: 2H H 2 0 Reactants (H & O) Products (water) Notes

Chapter 7 SPI Reactants & Products SPI Law of Conservation of Mass  Chemical Equations show how chemical reactions occur, and the must obey the law of conservation of mass  The law of conservation of mass: Atoms are never lost or gained in a chemical reaction, they are just rearranged. Example: Look at the following equation. It does not obey the law of conservation of mass and is called unbalanced (count the atoms on each side!) H 2 + O 2 H 2 O 2 & 2 2 & 1 Four is not equal to three! Notes

Chapter 7 SPI Reactants & Products SPI Law of Conservation of Mass  Balancing Equations: make sure the number of reactants atoms equals the number of products atoms. If they are not equal, you must balance the equation (See below for an example) Same equation, but now I have balanced it (count the atoms on each side) 2H 2 + O 2 2H 2 O  Coefficient=number in front of a chemical symbol or formula (tells you to multiply) Subscript=small number below and to the right of a chemical symbol (tells you the number of atoms) Notes 4 Hyd + 2 Oxy yields 4 Hyd and 2 Oxy 6 reactant atoms is equal to 6 product atoms!