How many moles of pcl5 can be produced from 57.0 g of cl2 (and excess p4) ?

The reaction will take place according to the equation;

P4 + 10Cl2 = 4PCl5

1 mole of Cl2 contains 70.9 g/mol

Therefore, the number of moles of Cl2 will be;

= 57 g / 70.9 g/mol

= 0.804 moles

The mole ratio of Cl2 : PCl5 = 10:4

Therefore; the number of moles of PCl5 = (0.804/10) * 4

= 0.3216 moles