Sulfur oxide (6) with a mass of 8 g was dissolved in 142 g of a sulfuric acid solution with a mass fraction of H2SO4

Sulfur oxide (6) with a mass of 8 g was dissolved in 142 g of a sulfuric acid solution with a mass fraction of H2SO4 of 10%. Determine the mass fraction of H2SO4 in the resulting solution.

Find the mass of sulfuric acid in the solution.

The mass fraction of a substance is calculated by the formula:

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

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

m (substance) = (142 g × 10%): 100% = 14.2 g.

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

M (H2SO4) = 98 g / mol.

n = m: M.

n = 14.2 g: 98 g / mol = 0.1 mol.

M (SO3) = 80 g / mol.

n (SO3) = 8 g: 80 g / mol = 0.1 mol.

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

H2O + SO3 = H2SO4.

According to the reaction equation, there is 1 mol of sulfur oxide for 1 mol of acid. Substances are in quantitative ratios 1: 1.

The amount of substance will be the same.

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

Let’s find the mass of sulfuric acid by the formula:

m = n × M,

M (H2SO4) = 98 g / mol.

m = 0.1 mol × 98 g / mol = 9.8 g.

m (H2SO4) = 9.8 g + 14.2 = 24 g.

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

m (solution) = 8 g + 142 g = 150 g.

W = (24g: 150g) × 100% = 16%.

Answer: 16%.