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The Equilibrium Dissociation and Thermodynamic Constants of Nitrosyl Chloride. Comparison with Spectroscopic Data

Beeson, Carrol M. and Yost, Don M. (1939) The Equilibrium Dissociation and Thermodynamic Constants of Nitrosyl Chloride. Comparison with Spectroscopic Data. Journal of Chemical Physics, 7 (1). pp. 44-52. ISSN 0021-9606. https://resolver.caltech.edu/CaltechAUTHORS:20140805-114545350

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Abstract

Careful measurements of the equilibrium dissociation of nitrosyl chloride into nitric oxide and chlorine have been made in the temperature range 100–220°. Pressure‐temperature measurements at 0°‐100° on mixtures of nitrosyl chloride and nitric oxide were made and from them the second virial coefficients of nitrosyl chloride gas were calculated. These vary from -389 cm^3/mole at 0° to -196 cm^3/mole at 100°. The virial coefficients were used to correct the measured equilibrium constants to those for perfect gases. Equations for free energy, entropy and heat content changes accompanying the dissociation were derived as functions of the temperature. The experimentally found entropy changes for the reaction were found to be less than those calculated from spectroscopic data by 3.61±0.3 cal./deg. To attain agreement, the spectroscopic entropy of nitrosyl chloride must be increased by 1.8 cal./deg., and this was attained by assuming that an observed infra‐red frequency at 923 cm^(‐1) is a combination, 633+290 cm^(‐1). For the reaction 2NOCl(g) = 2NO(g)+Cl_2(g), ΔF°_(298)=9,720±60 cal., ΔS°_(298)=28.0±0.5 cal./deg. ΔH°_(298)=18,060±200 cal. S°_(298)(NOCl)=63.0±0.3 cal./deg.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1063/1.1750323DOIArticle
http://scitation.aip.org/content/aip/journal/jcp/7/1/10.1063/1.1750323PublisherArticle
Additional Information:© 1939 American Institute of Physics. (Received September 6, 1938).
Issue or Number:1
Record Number:CaltechAUTHORS:20140805-114545350
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20140805-114545350
Official Citation:The Equilibrium Dissociation and Thermodynamic Constants of Nitrosyl Chloride. Comparison with Spectroscopic Data Beeson, Carrol M. and Yost, Don M., The Journal of Chemical Physics, 7, 44-52 (1939), DOI:http://dx.doi.org/10.1063/1.1750323
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:47978
Collection:CaltechAUTHORS
Deposited By: George Porter
Deposited On:05 Aug 2014 22:36
Last Modified:03 Oct 2019 06:59

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