Download Chemical Equation - Franklin Regional Middle School

Chemical Reactions
And
Balancing Chemical Equations
Vocabulary Terms
Compound
A molecule that contains at least
two different atoms in an exact
proportion.
The
atoms
in this compound
This
compound
has a
are being held together by
set
proportion
of
the energy and forces created
TWO
to ONE
by sharing
electrons
between
the atoms.
Chemical Changes
Changing the makeup of a substance.
Something
is created!
Signs ofNEW
a Chemical
Change:
Heat
Sound
Smell
Light
Examples of things made by chemical reactions:
Chemical Changes
Matter is Never created or destroyed
A chemical change takes “old” atoms and
Rearranges them into something New.
Reactant
Reactant
#1
#2
PRODUCT(s)
TYPES of Chemical Changes
Combustion Reaction is a type of
chemical change in which a substance
reacts with OXYGEN to produce energy.
When things burn, new things are made.
Heat Ash Light
(1) Fuel
This type of
reaction requires
THREE things
(2) Oxygen
(3) Spark
TYPES of Chemical Changes
Synthesis Reaction is a type of
chemical change in which two or more
substances combine to form a new
substance
Na
Sodium
Metal
Cl
Na Cl
Sodium Chloride
(NaCl)
Chlorine
Gas
Sodium
is
a
soft
metal
NaCl = regular ordinary, This
that when placed in
everyday…….
water will actually……
EXPLODE!
is a
Poisonous
gas.
TYPES of Chemical Changes
Double Replacement is a type of
chemical change in which the positive ion
from one compound switches places with
the positive ion from another compound
to form TWO new substances
NaCl + KBr
NaBr + KCl
Chemical Changes
Celebrity
Double Replacements
happen all the time
Double
(Even when there is no “CHEMISTRY”)
Replacement
Chemical Equations
The way that scientist represent and explain a
chemical reaction using the elements’ symbols
Think of chemical equations like
simple math addition problems!
In math, you learned that both sides of
the equation have to be equal.
5
= 10
+ 5
10
=
10
H
H
H
Hydrogen
Gas
H
H
O O
Hydrogen
Gas
Oxygen
Gas
Chemical Equation:
2H2 + O2
2H2O
H
O
H
H
O
Water
(H2O)
Chemical Equations
EXAMPLE Chemical Equation:
2H2 + O2
How many H’s are on
the LEFT side?
4
How many O’s are on
the LEFT side?
2
=
2H2O
How many H’s are on
the RIGHT side?
4
How many O’s are on
the RIGHT side?
2
Balancing Chemical Equations
By making both sides of a chemical equation
equal, it tells scientist what amount of
REACTANTS are necessary to make a certain
amount of the PRODUCTS.
Balancing chemical equations requires you to
follow rules and understand how to write an
atom’s symbol
Every atom symbol is like your name…
It begins with a capital letter
C
Carbon
or
Cl
Chlorine
Balancing Chemical Equations
Follow these rules
(1) After looking at the equation, Write down the
number of atoms of each element on each side
of the equation.
EXAMPLE Chemical Equation:
C3H8 + O2
C=3
H=8
O=2
H2O + CO2
C=1
H=2
O=3
Balancing Chemical Equations
(2) Choose an Atom to Balance
• Always leave H and O for Last
• Start with an atom that appears as a single
on either side (Products or Reactants)
EXAMPLE Chemical Equation:
C3H8 + O2
C=3
H=8
O=2
H2O + CO2
C=1
H=2
O=3
Balancing Chemical Equations
(3) Add a Coefficient Number to the single atom to
equal the amount of that atom on the other side.
Don’t forget to adjust your numbers before continuing.
EXAMPLE Chemical Equation:
C 3H 8 + O 2
H2O + 3 CO2
C=3
H=8
O=2
C=1 =3
H=2
O=3 =7
Balancing Chemical Equations
(4) Once you get to H and O, normally you will want
to balance the Hydrogens before the Oxygens.
Remember to adjust your numbers again before
continuing.
EXAMPLE Chemical Equation:
C 3H 8 + O 2
C=3
H=8
O=2
4H2O + 3CO2
C=3
H=2=8
O = 7 = 10
Balancing Chemical Equations
(5) Lastly balance the Oxygens.
Remember to adjust your numbers again before
continuing.
EXAMPLE Chemical Equation:
C3H8 + 5 O2
C=3
H=8
O = 2 = 10
4H2O + 3CO2
C=3
H=8
O = 10
Balancing Chemical Equations
(6) Some equations will only balance by using
½ coefficients. But ½ atoms DO NOT exist.
To Fix this problem simply DOUBLE ALL coefficients after
you have the equation balanced.
EXAMPLE Chemical Equation:
2FeS + 3½O2
S=2
Fe = 2
O=2=7
Fe2O3 + 2SO2
S=2
Fe = 2
O=7
Balancing Chemical Equations
Notice that ALL products and
reactants are still equal, but now
there are no ½ atoms.
EXAMPLE Chemical Equation:
4FeS + 7O2
S=4
Fe = 4
O = 14
2Fe2O3 + 4SO2
S=4
Fe = 4
O = 14
Balancing Chemical Equations
By making both sides of a chemical equation
equal, it tells scientist what amount of
REACTANTS are necessary to make a certain
amount of the PRODUCTS.
Let’s see if you can Balance this Equation:
Identify any coefficient number for each item.
_Zn + _2 HCl
Zinc
Hydrochloric
Acid
_ZnCl2 + _H2
Zinc
Chloride
Hydrogen
Gas
Balancing Chemical Equations
A Chemical Reaction occurs when you combine
Potassium Chlorate (KClO3)
with a
Gummy Candy (C6H12O6).
What Products do you think will be made?
KCl
CO2
H2O
Potassium
Chloride
Carbon
Dioxide
Water
(Steam)
Light
Heat
Balancing Chemical Equations
Let’s see if you can Balance this Equation:
Identify any coefficient number for each item.
_4KClO3 + _C6H12O6
Potassium
chlorate
Glucose (sugar)
_KCl + _6CO2 + 6_H2O
4
potassium
chloride
Carbon
dioxide
Water