40.0 g of a solute is dissolved in 500. mL of a solvent to give a solution with

Question

40.0 g of a solute is dissolved in 500. mL of a solvent to give a solution with a volume of 515 mL. The solvent has a density of 1.00 g/mL. Which statement about this solution is correct? (A) The molarity is greater than the molality. (B) The molarity is lower than the molality. (C) The molarity is the same as the molality. (D) The molarity and molality cannot be compared without knowing the solute.
Answer is B. Why is that? 40.0 g of a solute is dissolved in 500. mL of a solvent to give a solution with a volume of 515 mL. The solvent has a density of 1.00 g/mL. Which statement about this solution is correct? (A) The molarity is greater than the molality. (B) The molarity is lower than the molality. (C) The molarity is the same as the molality. (D) The molarity and molality cannot be compared without knowing the solute.
Answer is B. Why is that? 40.0 g of a solute is dissolved in 500. mL of a solvent to give a solution with a volume of 515 mL. The solvent has a density of 1.00 g/mL. Which statement about this solution is correct? (A) The molarity is greater than the molality. (B) The molarity is lower than the molality. (C) The molarity is the same as the molality. (D) The molarity and molality cannot be compared without knowing the solute.
Answer is B. Why is that?

Explanation / Answer

molarity = moles of solute/ liter of solution = 40/M/0.515= 77.66/M, M= molar mass of solute

volume of 40 gm of solute= 515-500=15ml

volume of solvent = 500ml, density =1 g/ml, mass of solvent = volume*density= 500*1= 500gm= 0.5Kg

Molality= moles of solute/kg of solvent =40/(0.5M)= 80/M

hence molarity is less than molality.

Related Questions

Navigate

• Browse (All)
• Browse 4
• Subjects

---