- 2 A Student Collected The Following Data For A Pure Naphthalene And A Solution Of An Unknown In Naphthalene And Drew Th 1 (138.79 KiB) Viewed 148 times
questions. Thank you.
2) A student collected the following data for a pure naphthalene and a solution of an unknown in naphthalene and drew the cooling curve. Mass of test tube,g Mass of test tube plus naphthalene, 8 Mass of test tube plus naphthalene plus unknown, g Molal freezing point depression constant, Kt of naphthalene, °C. kg/mol 20.071 23.122 23.530 6.4 Naphthalene/Unknown Pure Naphthalene Table A. Molecular Weight 80 Molecule Temperature, °C, 75 D M.W. (g/mol) 182.21 147.71 122.12 Benzophenone p-dichlorobenzene Benzoic acid 70 65 0 2 4 6 Time, min 8 10 a) (5 pts.) Calculate the mass of the unknown. b) (3 pts.) Read the freezing point of pure naphthalene. c) (3 pts.) Read the freezing point of naphthalene/unknown solution. d) (4 pts.) Calculate the freezing point depression. e) (5 pts.) Calculate the molality of naphthalene/unknown solution. f) (4 pts.) Calculate the molar mass of the unknown. g) (1 pt.) Suppose that the unknown is one of the substances in the table A, which one might it be?