The amount of urea ( NH₂CONH₂ ) required to prepare 500 mL of a decimolar aqueous solution is : (Molar mass of urea : 60 g mol ⁻¹ )

Step-by-step solution

A decimolar solution means the molarity is 0.1 M . The formula for molarity ( M ) is: M = w 1000 M_w V Where: w = mass of solute M_w = molar mass of urea = 60 g mol ⁻¹ V = volume of solution in mL = 500 mL Substituting the values: 0.1 = w 1000 60 500 0.1 = w 2 60 w = 0.1 60 2 = 3.0 g Thus, 3.0 g of urea is required. Answer: 3.0 g