In order to solve any stoichiometry problem. you must first write a balanced stoichiometric equation:
xA + yB —> wC + zD
This equation is read as:
x moles of A react with y moles of B to yield w moles of C and z moles of D.
Using the above general equation as an example. the calculations below show how to calculate the mass of C that is produced when 3 moles of A reacts with an excess of B (i.e.. A is the limiting reactant):