Conservation of mass

• You already know how to read SUBSCRIPTS

• A subscript tells us how many of each atom there are

• Add a subscript of 2 after Oxygen and you make Hydrogen Peroxide.

• The large number in FRONT of the symbol. You have to multiply this number by all of the subscripts.

• 4 Iron Atoms

• 6 Oxygen Atoms

• Follow the Law of Conservation

• Have the same number and type of atoms on both sides

• They just get rearranged!

The hydrogen are balanced, but the oxygens are not.

You CAN change the coefficient.

You CANNOT change the subscript.

We put a two in front of the water and this balances the oxygen.

H₂ + O₂ ---> 2H₂O

H₂ + O₂ ---> 2H₂O

• This causes the hydrogen to become unbalanced.

• To fix this, we place a two in front of the hydrogen on the left side.

  2H₂ + O₂ ---> 2H₂O

• It's balanced now!

• 4 H and 2 O

# of each element in reactants

MUST EQUAL

# of each element in products

Balance this equation.

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Balance this equation.

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Balance this equation.

Balance this equation.

Balance this equation.