Chapter 13 - Problems Solving Pahlavan

CHAPTER 12- Practice Exercise Dr. PAHLAVAN_ Physical Properties of Solutions Concentration problems

Problem #1. A 3.0 g sample of ground water contains 3.5 ppm of Arsenic ion. Calculate; (a) How many grams Arsenic ion are in this sample? What is the weight percentage of Arsenic ion? (b) If 0.25 L aqueous solution with density of 1.00 g/ml contains 13.7 g of pesticide, express the concentration in ppm and ppb.

Problem #2. An Antifreeze mixture is 11.0 molal ethylene glycol solution. Water is the solvent and it has a mass of 800 g. What is the mass of the solution? The molar mass of ethylene glycol is 62.0 g/mol

Problem #3. Calculate the molarity and molality of a solution that contains 18.0% HCl by mass and has a density of 1.05 g/ml.

Problem #4. What is the molality of a 2.50 M aqueous solution of ethanol, C2H5OH (molar mass = 46 g/mol)? with density 0.789 g/ml?

Problem #5. Calculate the concentration asked for in each problem. o (a) The molarity of 142 g of Na2CO3 in 2.00 L of solution at 0 C (a saturated solution). (b) The molality of 24.50 g of codeine, C18H21NO3 in 150.5 g of ethanol, C2H5OH. (c) The mole fraction of 32.3 g of NaCl in 265.0 g of H2O. (d) The mass percentage of HCl in a title cleaner containing 140 g of HCl and 800 g of H2O.

Problem #6 A 650.0 ml solution contains 19.6 g H2SO4. Calculate molarity and normality of the solution. Determine the number of equivalents of H2SO4.

Problem #7. A solution contains 10.0 g of KOH and 900.0 ml of water at 20oC. The volume of the solution is 904.7 ml. (a) Which component of the solution is the solute? Which is the solvent? (b) What is the molarity of the solution? (c) What is the molality of the solution? (d) What is the mass percentage of KOH? (e) What is the mole fraction of KOH? (f ) What is the normality of solution? Solubility & Pressure problems

’ o 4 Problem #8. The Henry s law constant (KH) for carbon monoxide, CO, in water at 25 C is 9.71x10 mol/L.atm . How many grams of CO will dissolve in 1.00 L of water if the partial pressure of CO is 2.75 atm ?

4 Problem #9. The solubility of N2 gas in water and N2 pressure of 1.0 atm is 6.9x10 M. What is the solubility (in mol/lit) of N2 gas in water at a N2 pressure of 0.80 atm? 1 Colligative Properties Problems

Problem #10. A solution is formed by dissolving 10.0 g of KCl in 500.0 g of H2O. o (a) What is the vapor pressure of the solution at 25 C if the vapor pressure of pure H2O is 23.8 mmHg at 25 oC? o (b) What is the boiling-point elevation? Kb for water is 0.52 C/m. o (c) What is the freezing-point depression? Kf for water is 1.86 C/m. (d) What is the osmotic pressure of the solution? Assume that the volume of the solution is 0.500 L.

Problem #11. Dimethyl gloxime, DMG, is an organic molecule used to test for aqueous nickel (II) ions. A solution prepared by dissolving 65.0 g of DMG in 375 g of ethanol boils at 80.3 oC. What is the molar mass of DMG? o o Kb = 1.22 C/m, and boiling point of pure ethanol = 78.5 C.

o ' Problem #12. A 0.100 m K2SO4 solution has a freezing point of (0.43) C. What is the Vant Hoff o factor (i) for the solution? Kf = 1.86 C/m

Problem #13. What is the vapor pressure of a solution made by dissolving 24.6 g of camphor (C10H16O) in 98.5 g of Benzene. Vapor pressure of benzene is 100.0 mmHg. (Camphor is a low-volatility solid).

Problem #14. A 0.500 L solution that contains 20.0 g of glucose has an osmotic pressure of 5.43 atm at 25 oC. What is the molar mass (MW) of glucose?

Problem #15. Compare the osmotic pressure, boiling point elevation, and freezing point depression of 0.10 M sucrose and 0.10 M NaCl aqueous solutions at 25 oC.

Problem #16. What is the molality of a 5.86 M ethanol ( C2H5OH = 46 g/mol) solution whose density is 0.927 g/ml. Ans. 8.92 mol/Kg

Problem #17. What is the freezing point of a solution containing 476 g of ethylene glycol (MW= 62.01 g/mol) in 3202 g water? Ans. (-4.48 0C)