When 80 g of SO3 was dissolved in water, 200 g of a sulfuric acid solution was obtained.

When 80 g of SO3 was dissolved in water, 200 g of a sulfuric acid solution was obtained. Find the mass fraction (b%) of H2SO4 in this solution. Mr (MgO) = 40, Mr (HCl) = 36.5

1. Dissolution of sulfuric acid anhydride in water proceeds according to the equation:

SO3 + H2O = H2SO4;

2. Calculate the chemical amount of sulfur oxide (6):

n (SO3) = m (SO3): M (SO3);

M (SO3) = 32 + 3 * 16 = 80 g / mol;

n (SO3) = 80: 80 = 1 mol;

3. Determine the amount of sulfuric acid:

n (H2SO4) = n (SO3) = 1 mol;

4. Let’s calculate the mass of sulfuric acid:

m (H2SO4) = n (H2SO4) * M (H2SO4);

M (H2SO4) = 2 + 32 + 4 * 16 = 98 g / mol;

m (H2SO4) = 1 * 98 = 98 g / mol;

5. Find the mass fraction of acid in the resulting solution:

w (H2SO4) = m (H2SO4): m (solution) = 98: 200 = 0.49 or 49%.

Answer: 49%.