Calculate the mass of urea required in making 2.5kg of 0.25 molar aqueous solution? which formula should I use mass by volume percentage or molality.help me out plz

Answer 1

0.25 M = 0.25 mols urea/L of solution by definition.
You don't give the density of the solution so I don't know where to begin. If you assume the density of the solution is 1.00 g/mL, which isn't true, then you want to make 2.5 L of solution.
0.25 M = ?mols/2.5 L
?mols = 0.25 x 2.5 = ?
Convert mols to grams urea by grams urea = mols urea x molar mass urea.