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Law of Conservation of Mass Practice (student handout)
Steps:
1. List the elements on both side of the equation.
2. Decide what color you are going to use for each element and fill in the dot with that color next to the element.
3. Using the colors you chose, draw the molecules for the reactants (left side).
4. Count the atoms of each element/color for the left side and fill in the table.
5. Calculate how that number of atoms would be recombined into products (right side) and fill in the missing
coefficients so that you have the same amount on both sides.
6. Draw the molecules of the products.
7. Count the number of atoms of each element on the product side and fill in the table.
8. Check that you have the same amount of each element on both sides.
Example:
3KOH + H3PO4 --------------------------->______K3PO4 + ____ H2O
1. 4NH3 + 5O2 -----------------> _____ NO + _____ H2O
Reactants (left side) Products (right side)
Element # of total atoms Element # of total atoms
Reactants (left side) Products (right side)
Element # of total atoms Element # of total atoms
Name: Class: Date:
