BalancingBalancingChemical ReactionsChemical Reactions
Why?Why?
There are laws!!!!There are laws!!!!
Matter cannot be created or Matter cannot be created or destroyed only changed. So if you destroyed only changed. So if you start with 20 hydrogen, you end start with 20 hydrogen, you end up with 20 hydrogenup with 20 hydrogen
EquationsEquations
Vinegar + Baking SodaVinegar + Baking Soda White Powder + Clear Liquid + Bubbles
Reactants Products
HC2H3O2 + NaHCO3 NaC2H3O2 + H2O + CO2
Word Equation
Formula Equation
Balancing a FormulaBalancing a Formula
HC2H3O2 + NaHCO3 NaC2H3O2 + H2O + CO2
HCCHHHOO + NaHCOOO NaCCHHHOO + HHO + COO
(5H, 3C, 5O, Na)
14 atoms
(5H, 3C, 5O, Na)
14 atoms
Balanced?Balanced?
Ag + HAg + H22SS AgAg22S + HS + H22Ag, 2H, S 2Ag, 2H, S
Ag + HAg + H22SS AgAg22S + HS + H22
2Ag, 2H, S 2Ag, 2H, S
If not….The ONLY thing you can do is multiply the number of MOLECULES you have. You do this by putting a
coefficient in front of the MOLECULE.2
The 2 multiplies everything after it until you have a different molecule.
Balance the followingBalance the following Na + HNa + H22O O NaOH + H NaOH + H22
Na=Na= Na=Na=
H =H = H =H =
O =O = O = O =
12
13
1
1
BALANCED
2
2
2
44
2Step 1: list all the elements underneath the reactants and products
22
2
Step 2: Count how many atoms of each element are on the reactant side and the product side
3rd Step: Put numbers (coefficients like 1, 2, 3, 4, 5 etc..) in front of the compounds that you are short on. This multiplies all of the atoms in the compound. When you do that, you may have to change the other side as well.
Why is it 4? Because 2 H from NaOH and 2 H from H2 are added
So what do we need to do?
Balance the followingBalance the following
HH22O + OO + O22 H H22OO22
H =H = H =H =
O =O = O = O =
23 2
2
So what do we need to do?
2
44
2
44
BALANCED
Step 1: list all the elements underneath the reactants and products
Step 2: Count how many atoms of each element are on the reactant side and the product side
3rd Step: Put numbers (coefficients like 1, 2, 3, 4, 5 etc..) in front of the compounds that you are short on. This multiplies all of the atoms in the compound. When you do that, you may have to change the other side as well.
Why did I put the 2 in front of H2O instead of O2?
Because only changing O2
would not help me with the H.
CaClCaCl22 Ca Ca22 + Cl + Cl22Ca=Ca= Ca=Ca=
Cl =Cl = Cl =Cl =21
22
42
4
2 2
BALANCED
Al + NaOH Al + NaOH Na Na33AlOAlO33 + H + H22
Al=Al= Al=Al=
Na=Na= Na =Na =
O =O = O =O =
H =H = H =H =
11
11
31
23
2
4
BALANCED
2
636
3
3
3 22
44
4
6
34
2
66
6
6
Now you do some at your deskNow you do some at your desk
Zn + HCl Zn + HCl ZnCl ZnCl22 + H + H22
Al + OAl + O22 Al Al22OO
Zn + Zn + HCl HCl ZnCl ZnCl22 + H + H22
Zn=Zn= Zn=Zn=
H=H= H =H =
Cl =Cl = Cl = Cl =
1
122
1
2
BALANCED
1 22
Al + OAl + O22 Al Al22OO
Al=Al= Al=Al=
O =O = O =O =
2
11
4 2
4
BALANCED
2
42
1.1. Zn + Zn + 22HCl HCl ZnCl ZnCl22 + H + H22
2.2. 1212Al + 3OAl + 3O22 66AlAl22OO