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The volume of a 27.0% (by mass) solution is 162.9 mL. the density of the solutio

ID: 492526 • Letter: T

Question

The volume of a 27.0% (by mass) solution is 162.9 mL. the density of the solution is 1.128 o/mL. What b the mass of solute in this solution? Concentrated sodium hydroxide is 19.4 M and has a density of 1.54 g/mL. What is the molality of concentrated NaOH? What is the freezing point of an aqueous 2.08 m NaCI solution? (K_fp for water is 1.858 degree C/m.) What is the freezing point of a 0.27 m solution of glucose. C_6H_12 O_6. in water? (K_fp for water is 1.858 degree C/m.) What is the freezing point of a solution containing 2.80 grams benzene (molar mass = 78.11 g/mole) dissolved in 43.0 grams paradichlorobenzene (molar mass = 147.0 g/mole)? the freezing point of pure paradichlorobenzene is 53.0 degree C and the freezing point depression constant, K_fp is -7.10 degree C/m. 14. A solution consisting of 0.21 mole of methylbenzene. C_6H_5CH_3. in 259 g of nitrobenzene. C_6H_5NO_2. freezes at 0.3 degree C. Pure nitrobenzene freezes at 6.0 degree C. What is the freezing-point depression constant of nitrobenzene? A 2.5-g sample of a small protein having a molecular weight of 72,000 g/mole is dissolved in 32.0 mL of water at 25 degree C. What is the osmotic pressure of the solution? (R - 0.0821 L atm/K mole; 1 atm - 760 mmHg)

Explanation / Answer

Given

Volume of solution = 162.9 ml

Density of solution = 1.128 g/ml

Mass of solution = Volume * density = 162.9 ml * 1.128 g/ml = 183.75 g

Given

Mass % = 27 % = 0.27 it means

Mass of solute / Mass of solution = 27 g / 100 g

Mass of solute = 0.27 * 183.75 g = 49.613 g

Answer for 9 is 49613 g

10)

Given Molarity = 19.4 M = 19.4 mol/L = No. of moles of solute / Volume of solution in L

basis 1 L of solution

density of solution = 1.54 g/ml

Mass of 1 L of solution = Volume * density = 1000ml * 1.54 g/ml = 1540 g

Given Molarity = 19.4 moles NaOH in 1 L of solution

Molar mass of NaOH = 40 g/mol

Mass of NaOH (solute) = 19.4 moles * 40 g/mol = 776 g

Mass of solvent = Mass of solution - mass of solute = 1540 - 746 = 764 g = 0.764 Kg

Molality = No. of moles of solute (NaOH) / Mass of solvent in Kg = 19.4 mol / 0.764 Kg = 25.4 mol/Kg

Molality = 25.4 m

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