Sulfur oxide (6) with a mass of 8 g was dissolved in 92. Sulfur oxide (6) with a mass of 8 g was dissolved in 92

Sulfur oxide (6) with a mass of 8 g was dissolved in 92. Sulfur oxide (6) with a mass of 8 g was dissolved in 92 g of water. Determine the mass fraction of sulfuric acid in the resulting solution.

Let’s find the amount of SO3 by the formula:

n = m: M.

M (SO3) = 80 g / mol.

n = 8 g: 80 g / mol = 0.1 mol.

Let’s find the amount of substance H2O by the formula:

M (H2O) = 18 g / mol.

n = 92 g: 18 g / mol = 5.11 mol (excess).

Let’s compose the reaction equation, find the quantitative ratios of substances.

SO3 + H2O = H2SO4.

According to the reaction equation, there is 1 mol of H2SO4 for 1 mol of SO3. Substances are in quantitative ratios 1: 1.

n (H2SO4) = n (SO3) = 0.1 mol.

Let’s find the mass of H2SO4.

m = n × M,

M (H2SO4) = 98 g / mol.

m = 0.1 mol × 98 g / mol = 9.8 g.

W = m (substance): m (solution) × 100%,

m (solution) = 92 g + 8 g = 100 g.

W = (9.8: 100) × 100% = 9.8%.

Answer: 9.8%.