1. FORMING NEW SUBSTANCES
Chapter 9 – 2 Part 4

2. Let’s review the Law of Conservation of Mass:
LET’S BEGIN AGAIN!
Let’s review the Law of Conservation of Mass:
The Law states that mass can neither be created nor destroyed in chemical or physical changes.

3. Balancing the Equation
Writing a balanced equation requires the use of a coefficient.
A coefficient is a number placed in front of a chemical symbol or formula.

4. Follow These Steps
To Success!

5. Step #1
Count the atoms of each element in the reactants and in the products.
__H2 + __O2 ––-> __H2O
Reactants Products
H ___ H ____
O ___ O ____
H _2_ H _2_
O _2_ O _1_

6. Step #2
To balance the oxygen atoms, place the coefficient 2 in front of the H2O.
__ H2 + __O2 –> 2 H2O
Reactants Products
H _2__ H_4_
O _2_ O_2_

7. Step #3
To balance the hydrogen atoms, place the coefficient 2 in front of the hydrogen’s formula.
2H2 + __O2 –> 2H2O
Reactants Products
H _4_ H_4_
O _2_ O _2_

8. Now do “Counting Atoms Practice” Let’s go on now!
Stop Here!
Now do “Counting Atoms Practice”
Let’s go on now!

9. LET’S TRY IT!
Conservation of Mass Lab