Using Moles to Balance Equations

If you know the masses of the REACTANTS and PRODUCTS that took part in a reaction, you can work out the BALANCED SYMBOL EQUATION for it.

You can do this by following these steps:

 

Step 1:

Find any unknown masses by using the CONSERVATION OF MASS.

 

Step 2:

Find the M_r for each reactant and product.

 

Step 3:

Divide the masses by the M_r for each reactant and product to find their MOLES.

 

Step 4:

Divide each of the moles by the SMALLEST NUMBER out of all of them.

 

Step 5:

If any of the values are NOT whole numbers, multiply all of them by a number that causes them to become WHOLE NUMBERS.

 

Step 6:

Put each of these numbers IN FRONT of their chemical formulas in the equation.

 

Example: