Question

A chemical supply company sells a concentrated solution of aqueous h2so4 (molar mass 98 g mol−1 ) that is 50. percent h2so4 by mass. at 25°c, the density of the solution is 1.4 g ml−1 . what is the molarity of the h2so4 solution at 25°c?

Answer 1

Answer is: the molarity of the sulfuric acid is 7.14 M.
ω(H₂SO₄) = 50% ÷ 100% = 0.5.
d(H₂SO₄) = 1.4 g/mL.
V(H₂SO₄) = 100 mL ÷ 1000 mL/L = 0.1 L..
mr(H₂SO₄) = d(H₂SO₄) · V(H₂SO₄).
mr(H₂SO₄) = 1.4 g/mL · 100 mL.
mr(H₂SO₄) = 140 g.
m(H₂SO₄) = ω(H₂SO₄) · mr(H₂SO₄).
m(H₂SO₄) = 0.5 · 140 g.
m(H₂SO₄) = 70 g.
n(H₂SO₄) = m(H₂SO₄) ÷ M(H₂SO₄).
n(H₂SO₄) = 70 g ÷ 98 g/mol.
n(H₂SO₄) = 0.714 mol.
c(H₂SO₄) = n(H₂SO₄) ÷ V(H₂SO₄).
c(H₂SO₄) = 0.714 mol ÷ 0.1 L.
C(H₂SO₄) = 7.14 M.