what is the percent by mass of solution (d =1,3g/ml) of urea ((NH2)2CO) with molarity 8,4mol/l?

Answer 1

% w/w = (grams solute/g solution)*100 = ?.

M = 8.4 mols/L.
mols = grams/molar mass so g = mols x molar mass = 8.4 x 62 = approx 521 g in the solution so g solute = approx 521.
The solution has a mass of 1.3g x 1000 = approx 1300 grams.

Now % = approx 521/1300)*100 = ?