Phosphorous trichloride (PCl3) is produced

from the reaction of white phosphorous (P4)
and chlorine:
P4(s) + 6Cl2(g) --> 4 PCl3(g) .
A sample of PCl3 of mass 280.7 g was collected from the reaction of 70.86 g of P4 with excess chlorine. What is the percentage yield of the
reaction?
Answer in units of %.

Answer with steps please! Thanks!