P5B.1 Potassium fluoride is very soluble in glacial acetic acid (ethanoic acid) and the solutions have a number of unusual properties. In an attempt to understand them, freezing-point depression data were obtained by taking a solution of known molality and then diluting it several times (J. Emsley, J. Chem. Soc. A, 2702 (1971)). The following data were obtained: b/(mol kg") 0.015 0.037 0.077 0.295 0.602 ΔΤΙΚ 0.115 0.295 0.470 1.381 2.67 Calculate the apparent molar mass of the solute and suggest an interpretation. Use AfH= 11.4kJ mol™ and T;* = 290 K for glacial acetic acid. lus

P5B.1 Potassium fluoride is very soluble in glacial acetic acid (ethanoic acid) and the solutions have a number of unusual properties. In an attempt to understand them, freezing-point depression data were obtained by taking a solution of known molality and then diluting it several times (J. Emsley, J. Chem. Soc. A, 2702 (1971)). The following data were obtained: b/(mol kg") 0.015 0.037 0.077 0.295 0.602 ΔΤΙΚ 0.115 0.295 0.470 1.381 2.67 Calculate the apparent molar mass of the solute and suggest an interpretation. Use AfH= 11.4kJ mol™ and T;* = 290 K for glacial acetic acid. lus

Chemistry

10th Edition

ISBN:9781305957404

Author:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste

Publisher:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste

Chapter17: Spontaneity, Entropy, And Free Energy

Section: Chapter Questions

Problem 128IP: Some nonelectrolyte solute (molar mass = 142 g/mol) was dissolved in 150. mL of a solvent (density =...

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Some nonelectrolyte solute (molar mass = 142 g/mol) was dissolved in 150. mL of a solvent (density = 0.879 g/cm3). The elevated boiling point of the solution was 355.4 K. What mass of solute was dissolved in the solvent? For the solvent, the enthalpy of vaporization is 33.90 kJ/mol, the entropy of vaporization is 95.95 J/K mol, and the boiling-point elevation constant is 2.5 K kg/mol.
3. Assume that toluene and hexane form an ideal solution. At 365 K pure toluene has a vapour pressure of 0.582 bar and pure hexane has a vapour pressure of 1.99 bar. Consider a solution with mole fraction of hexane = 0.250. (a) Calculate the partial pressures of toluene and hexane, and the total pressure above the solution. (b) Some of the vapour is removed and allowed to condense in a second container. Calculate the partial pressures of hexane and toluene and the total pressure above this solution.
P5B2 In a study of the properties of an aqueous solution of Th(NO3)² by A. Apelblat, D. Azoulay, and A. Sahar (J. Chem. Soc. Faraday Trans., I, 1618, (1973)), a freezing-point depression of 0.0703 K was observed for an aqueous solution of molality 9.6 mmol kg ¹. What is the apparent number of ions per formula unit? 24.0 10.0 TT.O 10.0 22.0 acid with PS te
which of the following is the correct answer in the image provided and explain your reason for the choice.
Phenol and water form non-ideal liquid mixtures. When 7.32 g of phenol and 7.95 g of water are mixed together at 60 °C they form two immiscible liquid phases with mole fractions of phenol of 0.042 and 0.161. (i) Calculate the overall mole fraction of phenol in the mixture. (ii) Use the lever rule to determine the relative amounts of the two phases.
5C. 2(b) Sketch the phase diagram of the system of NH/NH, given that the two substances do not form a compound; NH, freezes at -78 °C; N₂H, freezes at 2 °C; a eutectic is formed when the mole fraction of N H is 0.07; and the eutectic melts at -80 °C.
It is found that the boiling point of a binary solution of A andB with xA = 0.6589 is 88 °C. At this temperature the vapour pressuresof pure A and B are 127.6 kPa and 50.60 kPa, respectively. (i) Is thissolution ideal? (ii) What is the initial composition of the vapour abovethe solution?
The osmotic pressu re of an aqueous solution of urea at 300 K is 150 kPa. Calculate the freezing point of the same solution.
Calculate the solubility of 1,4-dibromobenzene in benzene at 25.000C and at 45.000 assuming that these two compounds form ideal mixtures. The enthalpy of fusion of 1,4-dibromo benzene is 20.39 kJ mol-1 and its melting point is 87.400C. Report the solubility of 1,4-dibromo benzene in benzene as (a) its mole fraction, and (b) grams of 1,4-dibromo benzene in 1000 grams of benzene.
An ideal-dilute solution of chloroform and ethanol with a mole fraction of ethanol in the liquid phase Xeth = 0.9900 has a total vapour pressure of p = 17795 Torr. The vapour pressure of pure ethanol at this temperature is p*eth = 172.76Torr. (a) Use Raoult's law to calculate the partial pressure of ethanol in the vapour phase. (b) Hence determine the partial pressure of chloroform in the vapour phase . (c) Also calculate the mole fractions of chloroform and ethanol in the vapour phase. (d) Calculate the Henry's law constant for chloroform, Kchl at this temperature.
(b) At 80 °C, ethylene dibromide and propylene dibromide mixture forms an ideal solution. Given that the pure vapour pressures of ethylene dibromide and propylene dibromide are 22.9 and 16.9 kPa, respectively. Using the plots of partial vapour pressures of ethylene dibromide and propylene dibromide, and total vapour pressure of the mixture against the mole fraction of ethylene dibromide, determine (i) the composition of the vapour in equilibrium with a solution containing 0.75 mole fraction of ethylene dibromide. (ii) the composition of the liquid phase in equilibrium with ethylene dibromide- propylene dibromide containing 0.5 mole fraction each.
3. (a) At 10 °C, the vapour pressures of pure chloroform (CHCI;) and pure dichloromethane (CH2CI2) are 101 mmHg and 235 mmHg, respectively. Assume that a solution made by mixing CHCI3 and CH;Cl2 is ideal. ii. Given the following data for this solution: p (CH2C12) = 1.33 gcm³; p (CHC13) = 1.48 gcm3; partial molar volume of CH2C12 = 56.5 cm³mol·'; partial molar volume of CHC13 = 77.3 cm³mol'. Calculate AmixV