1. Balancing Chemical Equations
Created by Kesler Science – More 5E lessons at KeslerScience.com
Presented by Kesler Science

2. Essential Questions:
What are the different parts of the chemical equation?
How can we tell if a chemical equation is balanced or not?
How does balancing equation relate to the law of conservation of mass?

3. Quick Action – INB Template
Directions for INB Template
Fold the paper along the dotted line.
Cut on the lines between each word up to the dotted line.
Paste the blank half of the page into your INB so that the flaps open up.
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4. 2 H2O Review Balancing Chemical Equations
Subscripts describe the # of atoms in a molecule
H2O Model
The Coefficient represents the number of molecules
2 Molecules of H2O 2
H2O H O H O
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5. 2H2 + O2  2 H2O Chemical Equation Balancing Chemical Equations
Broken into 3 main parts
Reactants
Arrow = Chemical Reaction
Products
RAP is an easy way to remember.
2H2 + O2  2 H2O
Reactants
Product
Arrow
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6. 2H2 + O2  2 H2O Reactants Balancing Chemical Equations
Elements or compounds which exist PRIOR to a chemical reaction
4 atoms of Hydrogen
2 atoms of Oxygen
2H2 + O2  2 H2O
Reactants
Students should take these notes on the INB template.
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7. 2H2 + O2  2 H2O Products Balancing Chemical Equations
New substances that are created by the rearranging of atoms after a chemical reaction
2 molecules of water
4 hydrogen atoms
2 oxygen atoms
2H2 + O2  2 H2O
Product
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8. 2H2 + O2  2 H2O Arrow/Chemical Reaction Balancing Chemical Equations
The arrow represents a chemical reaction.
Atoms are rearranged to form new substances
Atoms are not lost or gained; they must be equal on both sides
2H2 + O2  2 H2O
Arrow
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9. 6CO2 + 6H2O  C6H12O6 + 6O2 Quick Action
Work with a partner to find the following items:
List the Products
List the Reactants
What does the arrow Represent?
How many atoms of oxygen are on the product side?
How many atoms of hydrogen are on the reactant side?
BONUS: What process does this chemical reaction represent?
Answers:
C6H12O6 and O2
CO2 and H2O
Chemical reaction or chemical change 18 12
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10. Law of Conservation of Mass
Balancing Chemical Equations
Law of Conservation of Mass
Matter (atoms) can neither be created  nor destroyed.
Atoms can only be rearranged.
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11. Balancing Chemical Equations
Equal number of the same type of atom on each side.
If unbalanced, you can only change the coefficient to make it balanced.
You CANNOT change subscripts.
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12. Understanding Coefficients Na + Cl2  NaCl (unbalanced)
Equations without coefficients are known as skeleton equations
Na Cl2  NaCl (unbalanced)
reactants
product

13. Understanding Coefficients 2Na + Cl2  2NaCl (balanced)
To illustrate the Law of Conservation of Mass, we place coefficients in equations to show that mass is not created or destroyed.
2Na Cl2  2NaCl (balanced)
reactants
product Cl Na Na Cl Cl Na Na
These equations are called “balanced equations” because they show the same number of elements on each side.

14. Yes, this equation is balanced.
Understanding Coefficients
You can determine whether or not equations are balanced using a simple accounting method and the skill you just learned.
Is the following equation balanced?
4 Fe + 3 O2  2 Fe2O3
Reactants side Products side
___ Fe ___ 4 4
___ O ___ 6 6
Yes, this equation is balanced.

15. No, this equation is not balanced.
Understanding Coefficients
Is the following equation balanced?
Al + O2  Al2O3
Reactants side Products side
___ Al ___ 1 2
___ O ___ 2 3
No, this equation is not balanced.

16. Yes, this equation is balanced.
Understanding Coefficients
You can determine whether or not equations are balanced using a simple accounting method and the skill you just learned.
Is the following equation balanced?
2 K + 2 H2O  2 KOH + H2
Reactants side Products side
___ K___ 2 2
___ H ___ 4
2+2 4
___ O ___ 2 2
Yes, this equation is balanced.

17. No, this equation is not balanced.
Understanding Coefficients
Is the following equation balanced?
Al4C3 + H2O → CH4 + Al(OH)3
Reactants side Products side
___ Al ___ 4 1
___ C ___ 3 1
___ H ___ 2 7
___ O ___ 1 3
No, this equation is not balanced.

18. No, this equation is not balanced.
Understanding Coefficients and Balancing
Determining if an equation is balanced or not is a very simple task, but once again carelessness will cause an incorrect answer. Do NOT pretend to understand better than you really do. Make a table and get it RIGHT!
Is the following equation balanced?
N O2  N2O5
Reactants side Products side
___ N ___ 2 2
___ O ___ 6 5
No, this equation is not balanced.

19. Yes, this equation is balanced.
Understanding Coefficients
Is the following equation balanced?
For some of you, it will be easier to just ignore the polyatomic ions and focus on the other elements.
2LiI Pb(NO3)2  2LiNO PbI2
Reactants side Products side
___ Li ___ 2 2
___ I ___ 2 2
___ Pb ___ 1 1
__2_ NO3 _2__
Yes, this equation is balanced.

20. Determine if the equations in your notes are balanced or not using the accounting method.20

21. _____ Li _____ _____ N _____ 6 6 3 3 6 6 6 3 2 4 2 4 2 2 2 1
When you are given sets of coefficients, all you need to do is plug them in to see if they are balanced or not. Once again, this is a test of your patience more than anything else.
___Li ___N2 ___Li3N
A 6, 2, 2
B 3, 1, 2
C 3, 2, 1
D 6, 1, 2
_____ Li _____
_____ N _____ 6 6 3 3 6 6 6 3 2 4 2 4 2 2 2 1

22. Determine which set of coefficients on your notes will balance the equations.22

23. Always check every answer choice!
When you are given a molecule to place into the equation, the same principle applies.
C6H12O6
H2O2
2H2O
2CO
CH O CO ____
_____ C _____
_____ H _____
_____ O _____
A 2CO
B H2O2
C 2H2O
D C6H12O6 1 7 1 1 1 1 3 1 4 12 4 4 4 4 2 4 8 4 4 4 4 4 4
Always check every answer choice!

24. 2 Ag2O g Ag + O2 4 2 Balanced! Balancing Chemical Equations Practice
Step 1 – Take Inventory of the elements and atoms on the product and reactant side. Step 2 – Is it balanced? Step 3 – If unbalanced, change coefficients until it’s balanced. 2
Ag2O g Ag O2 4 2
Ag – 2 O – 1 4 =
Ag – 1 O – 2 4 2 2
As of 2016 the Texas standards says student are to “recognize if a chemical equation is balanced using coefficients”.
For your on-level classes you could stop here. It’s either balanced or it isn’t.
For your advanced classes you could actually teach them how to balance the equation.
Balanced!
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25. Quick Action – INB Template
Directions for INB Template
Cut the paper out along the solid line.
Determine if the formulas are balanced or unbalanced.
Paste the template into your INB.
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26. Quick Action – Balance the Equation
Step 1 – Take Inventory of the elements and atoms on the product and reactant side.
Step 2 – Is it balanced?
Step 3 – If unbalanced, change coefficients until it’s balanced.
NaBr + CaF2  NaF + CaBr2
Allow students to work with a partner
Answer: 2NaBr +CaF2  2NaF + CaBr2
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27. Quick Action – INB Template
Directions for INB Template
Cut out the INB template.
Do not cut the dashed lines
Paste them into your INB along the skinny tab so that the template folds up like an accordian.
I would only do this sheet in your advanced class unless you have to teach HOW to balance equations rather than determining if it is balanced or not.

28. Check for Understanding
Can you…
Recognize whether a chemical equation balanced or not?
Relate balanced equations to the law of conservation of mass.
Clear up any confusion and answer questions.
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