Find the mass of oxide P (V) if 6.2 g of phosphorus reacts with oxygen.

1. We write down the reaction equation:

4P + 5O2 = 2P2O5;

2.Calculate the chemical amount of phosphorus:

n (P) = m (P): M (P) = 6.2: 31 = 0.2 mol;

3.Let’s find the amount and mass of the resulting phosphorus oxide (5):

n (P2O5) = n (P): 2 = 0.2: 2 = 0.1 mol;

m (P2O5) = n (P2O5) * M (P2O5);

M (P2O5) = 2 * 31 + 5 * 16 = 142 g / mol;

m (P2O5) = 0.1 * 142 = 14.2 g.

Answer: 14.2 g.