Calculate the mass of phosphorus oxide 5 required to obtain phosphoric acid with a chemical amount of 0.05 mol.

| May 28, 2021 | education

Calculate the mass of phosphorus oxide 5 required to obtain phosphoric acid with a chemical amount of 0.05 mol. Determine the mass fraction of the solution obtained by dissolving the acid with the indicated amount in water weighing 1 kg.

Given:

n (Н3РО4) = 0.05 mol

m (H2O) = 1 kg = 1000 g

m (P2O5) -?

W (Н3РО4) -?

1) We write down the reaction equation and calculate the mass of P2O5:

P2O5 + 3 H2O = 2 H3PO4

M = 142 g / mol

m = 142 g

x = 142 g * 0.05 mol / 2 mol

x = 3.6 g (P2O5)

2) Calculate the mass fraction of acid in the solution:

W (Н3РО4) = m (Н3РО4) * 100% / m (solution)

M (H3PO4) = 98 g / mol

m (Н3РО4) = 0.05 mol * 98 g / mol = 4.9 g

m solution (Н3РО4) = 1000 g (Н2О) + 4.9 g (Н3РО4) = 1004.9 g

W (Н3РО4) = 4.9 g * 100% / 1004.9 g

W (H3PO4) = 0.49%

Answer: 3.6 g (P2O5), 0.49% (H3PO4)



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