There is 500 ml of a solution with a mass fraction of 40% nitric acid with a density of 1.25 g / cm.

There is 500 ml of a solution with a mass fraction of 40% nitric acid with a density of 1.25 g / cm. Determine the mass and amount of acid in this solution.

Given:
V solution (HNO3) = 500 ml
ω (HNO3) = 40%
ρ solution (HNO3) = 1.25 g / cm3 = 1.25 g / ml

To find:
m (HNO3) -?
n (HNO3) -?

1) m solution (HNO3) = ρ solution * V solution = 1.25 * 500 = 625 g;
2) m (HNO3) = ω * m solution / 100% = 40% * 625/100% = 250 g;
3) n (HNO3) = m / M = 250/63 = 3.97 mol.

Answer: The mass of HNO3 is 250 g; the amount of substance is 3.97 mol.