Answer to Question #155142 in General Chemistry for Alexis

Question

An aqueous solution of density d = 0.803 g / ml is prepared by dissolving 12.8 ml of propanol in 75 ml of water at 20 ° C. Calculate the percentage of propanol (a) by volume; (b) percentage by weight.

Answer 1

density = 0.803g/ml

12.8ml of propanol in 75ml water

%v/v = $\frac{12.8}{75+12.8}$ ×100

%v/v = $\frac{12.8}{87.8}$ × 100 = 14.57 %

12.8ml propanol

mass of propanol = (12.8×0.803)g = 10.2784g

mass of water = 75g

%w/w = $\frac{10.2784}{75+10.2784}$ ×100

%w/w = $\frac{10.2784}{85.2784}$ × 100 = 12.05%