What mass of phosphoric acid and water should be taken to prepare 450 grams of its 15% solution?

The mass of the acid solution is 450 grams;

To find the mass of the acid, it is necessary to multiply its mass fraction by the mass of the solution.

m acid = 450 x 0.15 = 67.5 grams;

To find the mass of water, subtract the mass of the acid from the mass of the solution:

m of water = 450 – 67.15 = 382.5 grams;

Check: 382.5 + 67.15 = 450;