Answer to Question #26315 in Physical Chemistry for judy chisenga

Question

How many moles of hydrosulphate acid are there in 27.0 g of hydrosulphate acid if the density of hydrosulphate acid is 1.84 g/cubic centimeter. what is the concentration in %m/m of 250 cubic centimeter in weighing 350 g?

Answer 1

To find the amount of H₂SO₄ in moles we should use the formula

n(moles) = m(g)/M_W(g/mol)
M_W(H₂SO₄) = 2 x 1 + 32 + 16 x 4 = 98 g/mol
n(H₂SO₄) = 27.0/98.0 = 0.276 mol
The concentration of H₂SO₄ is
w(%) = m(H₂SO₄, g)/m(solution of H₂SO₄, g) x 100%
The weight of 250 cm^3 of solution is
m(H₂SO₄) = V(cm^3) x p(g/cm^3) = 250 x 1.84 = 460 g
w(%) = 350 / 460 x 100% = 76.1 %

Answer:
n(H₂SO₄) = 0.276 mol
w(%) = 76.1 %