Textbook Problem

Phosphorus can be prepared from calcium phosphate by the following reaction:

$2{\text{Ca}}_3{\left({\text{PO}}_4\right)}_2\left(s\right)+6{\text{SiO}}_2\left(s\right)+10\text{C}\left(s\right)\to 6{\text{CaSiO}}_3\left(s\right)+{\text{ P}}_{\text{4}}\left(s\right)+10\text{CO}\left(g\right)$

Phosphorite is a mineral that contains Ca₃(PO₄)₂plus other non-phosphorus-containing compounds. What is the maximum amount of P₄ that can be produced from 1.0 kg of phosphorite if the phorphorite sample is 75% Ca₃(PO₄)₂ by mass? Assume an excess of the other reactants.