Download Balancing Equation Notes

Balancing Equation Notes
Why do we need to be balanced?
• So matter isn’t created or destroyed
– Remember the Conservation of Mass Law
Steps to balancing Equations
1. Count the # of atoms on each side
2. Add Coefficients where necessary
– hint: start with 2 and see where it gets you!
– NEVER CHANGE THE SUBSCRIPTS!
3. Recount the # of atoms on each side
4. Continue adding coefficients until the
number of atoms on each side are equal.
5. Reduce the coefficient to the lowest terms
HINTS TO REMEMBER
• Order for Balancing
– MI NOH  (Me Know)
• Metals
• Ions
• Non-Metals
• Oxygen
• Hydrogen
Step 1: Count the # of atoms of Each
Side
Mg + O2  MgO
Mg =
O=
Mg =
O=
Step 1: Count the # of atoms of each
side
Mg + O2  MgO
Mg = 1
O=2
Mg = 1
O=1
Step 2: Add Coefficients where necessary
• Are the numbers on both sides even?
– NO!  Add coefficients
Mg + O2  MgO
Mg = 1
O=2
Mg = 1
O=1
Step 2: Add Coefficients where necessary
• Are the numbers on both sides even?
– NO!  Add coefficients
Mg + O2  2MgO
Mg = 1
O=2
Mg = 1
O=1
Step 3: Recount the # of atoms on
each side
Mg + O2  2MgO
Mg = 1
O=2
• Are the atoms even now?
– No!
Mg = 1 2
O=1 2
Step 4: Continue adding coefficients until the
number of atoms on each side are equal.
Mg + O2  2MgO
Mg = 1
O=2
Mg = 1 2
O=1 2
Step 4: Continue adding coefficients
until the number of atoms on each
side are equal.
2Mg + O2  2MgO
Mg = 1 2
O=2
Mg = 1 2
O=1 2
Step 4: Continue adding coefficients
until the number of atoms on each
side are equal.
2Mg + O2  2MgO
Mg = 1 2
O=2
• Are they equal now?
– YES
– The equation is balanced!!!
Mg = 1 2
O=1 2
Step 4: Can You Reduce?
2Mg + O2  2MgO
Mg = 1 2
O=2
Mg = 1 2
O=1 2
• ALREADY REDUCED!!!
Practice Balancing Equations
• __Na + __Cl2  __NaCl
Practice Balancing Equations
• Step 1: Count atoms
__Na + __Cl2  __NaCl
Na = 1
Na = 1
Cl = 2
Cl = 1
Practice Balancing Equations
• Step 2: Add Coefficients
__Na + __Cl2  2 NaCl
Na = 1
Na = 1
Cl = 2
Cl = 1
Practice Balancing Equations
• Step 3: Recount Atoms
Na + Cl2  2 NaCl
Na = 1 Na = 1 2
Cl = 2
Cl = 1 2
Practice Balancing Equations
• Step 4: Continue adding
coefficients until atoms are equal
2 Na + Cl2  2 NaCl
Na = 1 2 Na = 1 2
Cl = 2
Cl = 1 2
Additional Practice
• __CH4 + __O2  __CO2 + __H2O
• __Li + __HNO3  __LiNO3 + __H2
• __Al + __O2  __Al2O3
Additional Practice
__CH4 + __O2  __CO2 + __H2O
C=1
C=1
H=4
O=2
H=2
O=3
Additional Practice
•CH4 + O2  CO2 + 2H2O
C=1
C=1
H=4
O=2
H=2 4
O=3 4
Additional Practice
•CH4 + 2O2  CO2 + 2H2O
C=1
C=1
H=4
O=2 4
H=2 4
O=3 4
Additional Practice
•Li + HNO3  LiNO3 + H2
Li = 1
Li = 1
H=1
H=2
N=1
N=1
O=3
O=3
Additional Practice
•Li + 2HNO3  LiNO3 + H2
Li = 1
Li = 1
H=1 2
H=2
N=1 2
N=1
O=3 6
O=3
Additional Practice
• Li + 2HNO3  2LiNO3 + H2
Li = 1
Li = 1 2
H=1 2
H=2
N=1 2
N=1 2
O=3 6
O=3 6
Additional Practice
2Li + 2HNO3  2LiNO3 + H2
Li = 1 2
Li = 1 2
H=1 2
H=2
N=1 2
N=1 2
O=3 6
O=3 6
Additional Practice
•Al + O2
Al = 1
O=2

Al2O3
Al = 2
O=3
Additional Practice
2Al + O2 
Al2O3
Al = 1 2
Al = 2
O=2
O=3
Additional Practice
2Al + O2 
2Al2O3
Al = 1 2
Al = 2 4
O=2
O=3 6
Additional Practice
2Al + 3O2 
2Al2O3
Al = 1 2
Al = 2 4
O=2 6
O=3 6
Additional Practice
4Al + 3O2 
Al = 1 2 4
O=2 6
2Al2O3
Al = 2 4
O=3 6