Question

6.2g of phosphorus was reacted with excess oxygen to form phosphorus( V) oxide. Determine the mass of the oxide formed. (0 = 16.0; P 31.0)

Answer 1

4P(s) + 5O₂(g) → 2P₂O₅(g)
Moles of P =  ^6.2/₃₁  = 0.2                           
Moles of P₂O₅ = ½ × 0.2 = 0.1moles
R.F.M of P₂O₅ = (31× 2) + ( 16×5) =142
Mass of P₂O₅ = 142 × 0.1 = 14.2g