The balanced equation for the above reaction is as follows P4 + 10Cl2 —> 4PCl5 P4 is the limiting reactant. Stoichiometry of P4 to PCl5 is 1:4 The mass of P4 reacted = 23.0 g Number of P4 moles = 23.0 g/ 124 g/mol = 0.185 mol According to the stoichiometry the number of PCl5 moles produced are 4 times the amount of P4 moles reacted Therefore PCl5 moles = 0.185 x 4 = 0.74 mol