Answer to Question #185997 in Chemistry for Hossein

Question

the density of concentrated ammonium hydroxide which contain 28 wt% NH3 is 0.899 g/ml. what volume of this reagent should be dilute to 500ml to make 0.25M NH3?

Answer 1

С_M = n / V

n (NH₃) = C_M x V = 0.25 x 0.5 = 0.125 mol

n = m / M

M (NH₃) = 18 g/mol

m (NH₃) = n x M = 0.125 x 18 = 2.25 g

m1 (NH₃) = (2.25 x 100) / 28 = 8.04 g

density = m / V

V₁ (NH₃) = m / d = 8.04 / 0.899 = 8.94 ml