In water weighing 120 g, 5 g of phosphorus oxide (5) was dissolved by heating.

In water weighing 120 g, 5 g of phosphorus oxide (5) was dissolved by heating. Calculate the mass fraction of orthophosphoric acid in the resulting solution.

Given:

m (water) = 120g,

m (P 2O5) = 5g.

Calculate mass fraction of H 3PO 4

Solution:

Solution mass = mass (water) + mass of solute:

m (solution) = 120g + 5g = 125g;

w = m (substance): m (solution) x 100%;

Mass fraction (H 3PO 4) = (5g: 120g) x 100% = 6%.

Answer: mass fraction of phosphoric acid 6%