In: Chemistry
Phosphate rock contains 80 percent of the compound 3Ca3(PO4)2.CaF2. (a) How much phosphorous is contained in 100 lb of phosphate rock? (b) How much equivalent phosphorous pentoxide P2O5 is contained in 100 lb of phosphate rock?
Ans. #1. Given- Mass of phosphate rock = 100 lb = 45.3592 kg = 45359.2 g
# Mass of Ca3(PO4)2.CaF2 in phosphate rock = 80% of 45359.2 g = 36287.36 g
# 1 mol Ca3(PO4)2.CaF2 (MW = 388.2515304 g/ mol) consists of 1 mol P (MW = 30.973762 g/ mol). So, 388.2515304 g Ca3(PO4)2.CaF2 is equivalent to 30.973762 g P.
So,
Mass of P = (30.974 g P / 388.25 g Ca3(PO4)2.CaF2) x 36287.36 g Ca3(PO4)2.CaF2
= 2894.92 g = 2.89492 kg = 6.382 lb
#2. 1 mol Ca3(PO4)2.CaF2 (MW = 388.2515304 g/ mol) consists of 1 mol P2O5 (MW = 141.944524 g/ mol). So, 388.2515304 g Ca3(PO4)2.CaF2 is equivalent to 141.944524
g P2O5.
So,
Mass of P = (141.945 g P2O5 / 388.25 g Ca3(PO4)2.CaF2) x 36287.36 g Ca3(PO4)2.CaF2
= 13266.724 g = 13.267 kg = 29.25 lb