Transcript Chemical Equations

Chemical Equations
EQ: What are the reactants and
products of a chemical reaction?
SPI 0807.9.10
What’s a Chemical Reaction?
• Chemical Reaction
process of a substance completely
changing to a different substance with
different properties.
Equations are made up of chemical
symbols and formulas.
• Chemical Symbol
Shorter way to write an element’s
name.
• Examples:
– H: Hydrogen
– O: Oxygen
– Fe: Iron
• Chemical Formula
combination of chemical symbols and
numbers to represent a substance.
• It’s an easy way to write molecules
and compounds.
• Examples:
– H2O: Water
– CO2: Carbon Dioxide
Counting Numbers
of Elements and Atoms
Name
Chemical
Formula
Number of
elements
Total
number of
atoms
Baking Soda
NaHCO3
?
?
Name
Chemical
Formula
Number of
elements
Total
number of
atoms
Water
H2O
?
?
Subscript
• Subscript
the small # to the right of the element
that tells the # of atoms
• Applies to only the element directly before
it!
Examples of subscripts:
–H2O
–SO4
–Ca(OH)2
H 2O
C6H12O6
MgCl2
C12H22O11
Ca(OH)2
Take inventory…
1. CO2
2. H2O
3. NaClF4
Coefficients
• Coefficients
large # to the left of the element.
• Applies to the whole molecule!
Examples of coefficients:
– 2H2O
– 4SO4
– 3Ca(OH)2
2NH3
4NaClO
2CaCO3
Take inventory of the following
compounds:
1.
4 NaCl
2.
6 CO2
3.
2 H2O
• CH4
• 3CO3
• 2Na2OH3
Take inventory of the following
compounds:
• 3P2O5
• C3(FO4H2)2
• 2Ca(H2PO4)2
EQ: What are reactants and
products in a chemical equation??
SPI 0807.9.10
•
Reactants
what you start with
•
Products
what you end with
REACTANTS
PRODUCTS
BEFORE THE
ARROW
AFTER THE
ARROW
Copy this equation.
Circle the REACTANTS
and underline the PRODUCTS.
How many atoms of each element are
there?
CH4 + O2 → CO2 + H2O
CH4 + 2O2  CO2 + 2H2O
H2CO3  H2O + CO2
NH4OH  NH3 + H2O
The Law of
Conservation of Mass
EQ: What is the Law of
Conservation of Mass?
SPI 0807.9.11
The Law of Conservation of Mass
• Law of conservation of Mass
states that mass cannot be created
or destroyed!
4Na + 2Cl2  4NaCl
This is important when we balance
equations…
• An equation is balanced when the #
of atoms in the reactants are = to the
# of atoms in the products.
Is this a balanced equation?
Na + Cl2  2NaCl
Is this a balanced equation?
6 CO2 + 6 H2O  C6H12O6 + 3 O2
Is this a balanced equation?
• You balance an equation by
changing the coefficients, not
the subscript!
Balance this equation.
___ Mg + ___ O2
___ MgO
Balance the equation.
___ H2O2
___H2O + ___ O2
__ Fe + __S → __FeS
__H2 + __O2 → __H2O
__Mg + __O2 → __MgO
_Ca + _H2O → _Ca(OH)2 + _H2
___ NH4NO3  ___ N2O + ___ H2O
___BKClO3  ___BKCl + ___BO2
___ C3H8 + ___O2  ___ CO2 + ___ H2O
__ Al2O3 + __ Fe  __ Fe3O4 + __ Al
___ P4O10 + ___H2O  ___H3PO4
__Al + __H2SO4  __Al2(SO4)3 + __H2
__Be2C + __H2O  __Be(OH)2 + __CH4
___ Fe + ___ O  ___ Fe2O3
__S + __HNO3  __H2SO4 + __NO2 + __H2O
__NH3 + __CuO  __Cu + __N2 + __H2O
__Cu + __HNO3 __Cu(NO3)2 + __NO + __H2O
Al2(SO3)3 + NaOH  Na2SO3 + Al(OH)3