A 15.00 % by mass solution of lactose (C₁₂H₂₂O₁₁, 342.30 g/mol)in water has a density of 1.0602 g/mL at 20°C.What is the molarity of this solution? A)0.03097 M B)0.4133 M C)0.4646 M D)1.590 M E)3.097 M

Question

Quizplus · Accepted Answer

First, we need to calculate the mass of lactose present in the solution:

Mass of lactose = 15.00% × 1000 g (since density is given in g/mL) = 150 g

Next, we can calculate the moles of lactose present using its molar mass:

Moles of lactose = 150 g ÷ 342.30 g/mol = 0.4382 mol

Now, we need to calculate the total volume of the solution using its density:

Volume of solution = Mass of solution ÷ Density of solution = 1000 g ÷ 1.0602 g/mL = 942.1 mL

Finally, we can calculate the molarity of the lactose solution:

Molarity = Moles of solute ÷ Volume of solution (in L) = 0.4382 mol ÷ 0.9421 L = 0.4646 M

Therefore, the correct answer is C, 0.4646 M.

A 1500 % by Mass Solution of Lactose (C12H22O11, 342

A 1500 % by Mass Solution of Lactose (C₁₂H₂₂O₁₁, 342