Question

Calculate the molarity when 120 g of urea (Molar mass = 60 $gmo{l}^{-1}$) is dissolved in 600 mL water to form a solution.

• A. 3.33 M
• B. 4.00 M
• C. 2.45 M
• D. 6.10 M

Answer 1

The correct option is A 3.33 M

Molarity is defined as the number of moles of solute in 1L of the solution
Molarity (M)=$\frac{n_{\text{solute}}}{\text{volume of solution (mL)}}\times 1000=\frac{\text{weight of solute}\times 1000}{\text{molar mass of solute}\times \text{volume of solution (mL)}}$
$=\frac{120\times 1000}{60\times 600}=3.33$
Therefore, the molarity of the solution is 3.33 M