Question

What is the maximum amount in moles of P2O5 that can theoretically be made from 112 g of P4 and excess oxygen?

Answer 1

P₄ + 5O₂ = 2P₂O₅

n= m/M

M(P₄)= 30.97*4 = 123.88 g/mol

n(P₄)= 112g/123.88 g/mol = 0.904 mol

According to equation 1 mole of P₄ gives 2 moles of P₂O₅

We have 0.904 mol of P₄ which give x mol of P₂O₅

Solve the proportion:

1/0.904 = 2/x

x= 1.808

n(P₂O₅) = 1.808 mol

Answer: 1.808 mol