Chapter 7SPI 0807.9.10 Reactants & ProductsSPI 0807.9.11 Law of Conservation of Mass Bellwork
1
Turn to page 340, and read the 3rd 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 + O2 CO2
Chapter 7SPI 0807.9.10 Reactants & ProductsSPI 0807.9.11 Law of Conservation of Mass Bellwork
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1) Contrast reactants and products (how are they different?)Reactants-starting materials in a chemical reactions Always written before the arrow
C + O2 CO2
Chapter 7SPI 0807.9.10 Reactants & ProductsSPI 0807.9.11 Law of Conservation of Mass Bellwork
1
1) Contrast reactants and products (how are they different?)Reactants-starting materials in a chemical reactionsProducts-substances formed in a chemical reaction Always written after the arrow
C + O2 CO2
Chapter 7 SPI 0807.9.10 Reactants & ProductsSPI 0807.9.11 Law of Conservation of Mass
3 key TopicsChemical symbolsChemical FormulasChemical Equations
Notes
Chapter 7 SPI 0807.9.10 Reactants & ProductsSPI 0807.9.11 Law of Conservation of Mass
Key TopicsChemical 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 0807.9.10 Reactants & ProductsSPI 0807.9.11 Law of Conservation of Mass
Key TopicsChemical formulas
Notes
Chemical symbols combined together = chemical formulas
Examples: Put the symbols H and O together…And you get the formula for water… H2O
Chapter 7 SPI 0807.9.10 Reactants & ProductsSPI 08079.11 Law of Conservation of Mass
Key TopicsChemical symbols & Chemical Formulas
Notes
Very Important!!!symbols & formulas must be written correctly. CO2= one carbon atom, two oxygen atomsCO= one carbon atom, one oxygen atomCo=one cobalt atom2CO= two carbon atoms, two oxygen atoms2CO2= two carbon atoms, four oxygen atoms
Chapter 7 SPI 0807.9.10 Reactants & ProductsSPI 08079.11 Law of Conservation of Mass
Key TopicsChemical symbols & Chemical Formulas
Notes
QUICK REVIEW!
CO2
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 0807.9.10 Reactants & ProductsSPI 08079.11 Law of Conservation of Mass
Key TopicsChemical symbols & Chemical Formulas
Notes Nov 5, 2012
QUICK REVIEW!
CO2
Is this a chem symbol or chem formula?It is a chemical formula
Chapter 7 SPI 0807.9.10 Reactants & ProductsSPI 0807.9.11 Law of Conservation of Mass
Key TopicsChemical symbols & Chemical Formulas
Notes
QUICK REVIEW!
CO2
Is this a mixture or a compound? It is a compound
Chapter 7 SPI 0807.9.10 Reactants & ProductsSPI 08079.11 Law of Conservation of Mass
Key TopicsChemical symbols & Chemical Formulas
Notes
QUICK REVIEW!
CO2
How many total atoms does it contain?Three
Chapter 7 SPI 0807.9.10 Reactants & ProductsSPI 0807.9.11 Law of Conservation of Mass
Key TopicsChemical symbols & Chemical Formulas
Notes
QUICK REVIEW!
CO2
Identify the individual atoms.
= one carbon atom, two oxygen atoms
Chapter 7 SPI 0807.9.10 Reactants & ProductsSPI 0807.9.11 Law of Conservation of Mass
Key TopicsChemical Equations
Notes
Chemical formulas combined together = chemical equations
Examples:Equation: 2H2 + O2 2H2O
Equation: 2Na + Cl2 2 NaCl
Chapter 7 SPI 0807.9.10 Reactants & ProductsSPI 08079.11 Law of Conservation of Mass
2 parts of chemical equations (1) reactants (2) productsReactants: 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 withExample: 2H2 + 02 2H20
Reactants (H & O) Products (water)
Notes
Chapter 7 SPI 0807.9.10 Reactants & ProductsSPI 08079.11 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!) H2 + O2 H2O
2 & 2 2 & 1 Four is not equal to three!
Notes
Chapter 7 SPI 0807.9.10 Reactants & ProductsSPI 08079.11 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)2H2 + O2 2H2O
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 Oxy6 reactant atoms is equal to 6 product atoms!