Answer to Question #164418 in Chemistry for Phyroe

Question

Express in formality the concentration of 28.4 per cent in NH3 by weight having a density of 0.808 grams per ml.

Answer 1

C_M=n/V

n=m/M

M (NH₃) = 18 g/mol

Lets assume that we have 1 L of NH₃ solution.

density = m/V

m = density x V

m (NH₃)_solution = 0.808 x 1 = 0.808 kg

%= (100 x m_(solute))/(m_(solute)+m_(solvent))

m(NH₃) = (28.4 x 808)/100 = 229.5 g

n(NH₃) = 229.5/18 = 12.8 mol

C_M(NH₃) = 12.8/1 = 12.8 mol/L