Balance the chemical equation
Convert the amount of each reactant to moles
Use the mole ratio from the balanced equation to find how much product each reactant can form
Identify the reactant that produces the least amount of product; this is the limiting reactant
Use the limiting reactant to calculate the amount of the other reactant that is actually needed
Subtract the amount needed from the amount originally given for the excess reactant
Convert the remaining amount of excess reactant back to the desired unit if needed