1. Atoms must be conserved!
Balancing Equations
Atoms must be conserved!

2. What is balanced in a chemical equation?
Three things are balanced in a chemical equation:
1. Atoms
2. Mass
3. Charge

3. Balancing Atoms
For now, you will only be concerned with balancing atoms.
Remember, the number of atoms of each element on the reactants side must equal the number of atoms of each element on the products side!
Reactant =Product

4. Counting Atoms 1. H2SO4 2. Ca(OH)2 3. NaCl 4. (NH3)3P04 5. 3H2O
How many atoms of each element are in the following molecules?
1. H2SO4
2. Ca(OH)2
3. NaCl
4. (NH3)3P04
5. 3H2O
6. 4Al2(CO3)3

5. Answers 2 hydrogen, 1 sulfur, 4 oxygen 1 calcium, 2 oxygen, 2 hydrogen
3. 1 sodium, 1 chlorine
Now you try to do #4, 5 & 6.
Write your answers in your notes.

6. Is this equation balanced?
Ca + H2O Ca(OH)2 + H2
How do I know???

7. Step 1: Count Atoms Ca + H2O Ca(OH)2 + H2 Reactant Product Ca 1 Ca 1
Count the atoms on both sides of the equation.
Reactant Product
Ca Ca 1
H H 4
O O 2

8. Step 2: What is balanced? Ca + H2O Ca(OH)2 + H2 reactant product
Compare each element . Are there the same amount on both sides of the equation?
Ca + H2O Ca(OH)2 + H2
reactant product
Ca Ca 1
H H 4
O O 2

9. Step 3: What is balanced? If you have compared all the elements –
and they are equal on both sides you have a balanced equation.
If they are not you have an unbalanced equation.
We will learn how to balance equations in Chemistry.

10. Is this equation balanced?
NaCl + H2O  NaOH + Cl2
left 1Na, 1Cl, 2H, and 1O
right side has 1Na, 1O, 1H, and 2Cl
NO!!!!!!
It is not balanced!!

11. Is this equation balanced?
HCl + NaOH NaCl+ H2O
left side
2H, 1Cl, 1Na, and 1O
right side
1Na, 1Cl, 2H, and 1O
Yes!!!!!!
It is balanced!!

12. The End