What is the mass fraction of acid in a solution having the composition H2SO4 * 8H2O.

To calculate the mass fraction of acid in such a solution, it is necessary to find the mass fraction of water and acid molecules.

The mass fraction of the acid will be equal to the ratio of the molar masses of the pure acid to its hydrate.

M H2SO4 = 2 + 32 + 16 x 4 = 98 grams / mol;

M H2SO4 x 8 H2O = 2 + 32 + 16 x 4 + (2 + 16) x 8 = 242 grams / mol;

Let’s calculate this ratio.

With H2SO4 = 98/242 = 0.4049 = 40.5%;