Ca3(po4)2 + 3 sio2 + 5 c → 3 casio3 + 5 co + 2 p given the balanced reaction above, what mass (in grams) of phosphorus is produced if 36 g c react?

Answer is: mass of phosphorus is 37,16 grams.
m(C) = 36 g.
n(C) = m(C) ÷ M(C).
n(C) = 36 g ÷ 12 g/mol.
n(C) = 3 mol.
From balanced chemical reaction: n(C) : n(P) = 5 : 2.
n(P) = 2 · 3 mol ÷ 5.
n(P) = 1,2 mol.
m(P) = 1,2 mol · 30,97 g/mol.
m(P) = 37,16 g.

Both models are effective because they show the valence electrons, and these valence electrons indicate the reactivity of an element.