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

Chapter1: Chemical Foundations

Section: Chapter Questions

Problem 1RQ: Define and explain the differences between the following terms. a. law and theory b. theory and...

See similar textbooks

Similar questions

Estimate the vapour pressure of sea water at 20 °C given that the vapour pressure of pure water is 2.338 kPa at that temperature and the solute is largely Na+ and Cl- ions, each present at about 0.50 mol dm-3.
What proportions of benzene and ethylbenzene should be mixed (i) by mole fraction, (ii) by mass in order to achieve the greatest entropy of mixing?
The vapour pressures of benzene and methylbenzene at 20 °C are 75 Torr and 21 Torr, respectively. What is the composition of the vapour in equilibrium with a mixture in which the mole fraction of benzene is 0.75?
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 change in Gibbs energy that accompanies the combustion of C6H12O6(s) to carbon dioxide and water vapour at 25 °c is -2828 kJ mol-1. The potential energy of an object of mass m at a height h, relative to that at the Earth's surface is given by mgh, where g = 9.81 m s-2 is the acceleration of freefall. How much glucose does a person of mass 65 kg need to consume to climb through 10m?
Estimate the Gibbs energy change of 1.0 dm3 of liquid water when the pressure acting on it is increased from 100 kPa to 300 kPa, holding the temperature constant.
A solution is prepared by dissolving 2.33 g of C60 (buckminsterfullerene)in 100.0 g of toluene (methylbenzene). Given that the vapour pressure of pure toluene is 5.00 kPa at 30 °c, what is the vapour pressure of toluene in the solution?
Justify Raoult's and Henry's laws in terms of the molecular interactions in a mixture.
The following temperature-composition data were obtained for a mixture of octane (O) and methylbenzene (M) at 1.00 atm, where x is the mole fraction in the liquid and y the mole fraction in the vapour at equilibrium. The boiling points are 110.6oC and 125.6oC for M and O, respectively Plot the temperature-composition diagram for the mixture. What is the composition of the vapour in equilibrium with the liquid of composition (i)Xm =0.250 and (ii) Xo =0.250?
The variation of the vapour pressure of hexane may be written as In p = A- B/T, with A = 15.77 and B = 3811 K. What is (a) the enthalpy of vaporization, (b) the normal boiling point of hexane?
Comelli and Francesconi examined mixtures of propionic acid with various other organic liquids at 313.15 K (F. Comelli and R. Francesconi, J. Chem. Eng. Data 41, 101 (1996)). They report the excess volume of mixing propionic acid with tetrahydropyran (THP, oxane) as VE = x1x2{a0 + a1(x1 − x2)}, where x1 is the mole fraction of propionic acid, x2 that of THP, a0 = −2.4697 cm3 mol−1, and a1 = 0.0608 cm3 mol−1. The density of propionic acid at this temperature is 0.971 74 g cm−3; that of THP is 0.863 98 g cm−3. (a) Derive an expression for the partial molar volume of each component at this temperature. (b) Compute the partial molar volume for each component in an equimolar mixture.
Suppose that in a phase diagram, when the sample was prepared with the mole fraction of component A equal to 0.40 it was found that the compositions of the two phases in equilibrium corresponded to the mole fractions xA,α = 0.60 and xA,β = 0.20. What is the ratio of amounts of the two phases?