A Computer Program for Calculation of Dipole Moments from Oscillometric Data A straightforward computer program for calculating dipole moments of molecules in solution using the method of Halverstadt and Kt~mler[J. Am. Chem. Sac., 64, 2988 (1942) also: H. B., J. CHEM.EDUC.,43,66 (1966)l has been develTHOMPSON, oped far usein undergraduate physical chemistry or instrumental analysis laboratories. The program initially determines the cell constants for a. capacitance cell of the Sargent Model V Oscillometer using oscillometer scale readings from two or more standard liquids of known dielectric constant [see SEERRICK, P. H., DAWE,G. A,, KABR,R., AND EWEN,E. F., "Manual of Chemical Oscillometry," E. H. Sargent and Co., Chicago, 1954, p. 8.1. The two cell constants. are then employed to convert oscillometer scale readings of solutions to dielectric constants. The oscillometer readings, densities, and mole fractions of a series of solutions are used to calculate the molar polarization of solute in each solution. The densities, refractive indices, and molecular weights of pure solvent and solute are also necess a r y input parameters for these calculations. A least-squares analysis is employedto determine the molar polarization of the solute a t infinite dilution from the linear relationship of the molar ~olarizationsand mole fractions of the solute. The final ~ H I (,i I the pn Kwm i ~ v u l w tirr > c:~lcv.lntim of tht, d l p ~ l ci t . o r w r l t oi tlw rdute ~l..irzg lltr m ~ l i i rp d ~ r w . ~ t i of m st,lute at infinite d j l t l t ~ m ,the elrwtmic p d a r i , a u w i f thy a lute, nt.d the tm.perature of the solutions ~~
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Journal of Chemical Educafion
The program saves considerable time which would otherwise he spent in tedious, repetitious calculations, since a minimum of five solutions is desirable iar reasonably accurate results. The experiment illustrates the usefulness of the computer as a tool in chemical calculations and emphasizes the necessity for good laboratory technique in the collection of experimental data. Results hrwe been good (1.0-5.0% error) for experiments using solutions of nitrobenzene dissolved in benzene solvent. Concentrations of all solutions were less than 0.07 mole fraction of the solute. Directions far the experiment, inclnding a listing of the program (with an abundance of comment statements) written in FORTRAN 11, are available from the authors upon request. The aothars would like to express appreciation to the VMI Computer Center for assistance with this project.
