The major industrial method for the preparation of elemental phosphorus is heating a mixture of phosphate rock, carbon, and sand in an electric furnace. The chemical reactions can be represented by:
Ca3(PO4)2 + SiO2 --> CaSiO3 + P4O10
AND
P4O10 + C --> P4 + CO
A) Balance the equations
B) Calculate the percentage of Ca3(PO4)2 initially present in the rock sample if 307 kg of phosphate rock yields 42.5 kg of elemental P4.