Download Chemical Reactions

Chemical
Reactions
Chemical Reaction
A process in which one or
more substances are
converted into new
substances with different
physical and chemical
properties
Chemical Equations
Mg + S  MgS
Reactants – the elements/compounds
on the LEFT side of the equation
Products – the elements/compounds on
the RIGHT side of the equation
 - means “yields” or “produces”
Two way to write equations:
1. Word Equations
Ex: magnesium reacts with sulfur
to produce magnesium sulfide
2. Formula Equations
Ex: Mg + S  MgS
Diatomic Molecules
There are 7 elements on the
periodic table that cannot exist
alone. They will pair up with
each other in order be stable.
Those elements are:
If it says:
Write:
Hydrogen
H2
Oxygen
O2
Nitrogen
N2
Fluorine
F2
Chlorine
Cl2
Iodine
I2
Bromine
Br2
Word Equations with
Diatomics
When given a word equation with one of
those seven elements (only if they are an
element), you will use the diatomic form
in the formula equation.
Ex: sodium reacts with oxygen
Na + O2
not
Na + O
Write the formula equation for
the following word equation:
Oxygen reacts with sodium
fluoride to produce sodium
oxide and fluorine
O2 + NaF  Na2O + F2
Law of Conservation
of Matter
States that matter is not created
nor destroyed
Mass of Reactants = Mass of Products
Balancing Equations
You must make sure there are the SAME
NUMBER of each element on both sides
of the equation
Ex: 2Na + Br2  2NaBr
Coefficients – the numbers used to
balance an equation
Balance the following:
K + MgI2  KI + Mg
2K + MgI2  2KI + Mg
Ca(OH)2 + HCl  CaCl2 + H2O
Ca(OH)2 + 2HCl  CaCl2 + 2H2O