Deviations from Raoult's Law in H2O + D2O Liquid Mixtures

1979 ◽  
Vol 32 (1) ◽  
pp. 197 ◽  
Author(s):  
RC Phutela ◽  
DV Fenby
Keyword(s):  
Vapour Pressure ◽  
Boiling Point ◽  
Liquid Mixture ◽  
Isotope Effects ◽  
Liquid Mixtures ◽  
Raoult’S Law ◽  
Ideal Solutions ◽  
Good Agreement ◽  
Raoult's Law

Deviations from Raoult's law in H2O+D2O liquid mixtures are calculated from vapour pressure isotope effects for HDO and D2O by assuming that the equilibrium H2O+ HDO+D2O liquid mixtures are ideal solutions. The results are in good agreement with those obtained experimentally from liquid-mixture vapour pressure and boiling point measurements.

The entropy of liquid mixtures: I. The theory of Raoult's Law

1941 ◽  
Vol 60 (2) ◽  
pp. 76-84 ◽  
Author(s):  
A. J. Staverman ◽  
J. H. van Santen
Keyword(s):  
Liquid Mixtures ◽  
Raoult’S Law ◽  
Raoult's Law

scholarly journals Raoult’s law revisited: accurately predicting equilibrium relative humidity points for humidity control experiments

2016 ◽  
Author(s):  
Michael G. Bowler ◽  
David R. Bowler ◽  
Matthew W. Bowler
Keyword(s):  
Relative Humidity ◽  
Vapour Pressure ◽  
Control Device ◽  
Raoult’S Law ◽  
Simple Argument ◽  
Humidity Control ◽  
Saturated Vapour Pressure ◽  
Saturated Vapour ◽  
Equilibrium Relative Humidity ◽  
Raoult's Law

AbstractThe humidity surrounding a sample is an important variable in scientific experiments. Biological samples in particular require not just a humid atmosphere but often a relative humidity (RH) that is in equilibrium with a stabilizing solution required to maintain the sample in the same state during measurements. The controlled dehydration of macromolecular crystals can lead to significant increases in crystal order, which often leads to higher diffraction quality. Devices that can accurately control the humidity surrounding crystals on a beamline have led to this technique being increasingly adopted, as experiments become easier and more reproducible. Matching the relative humidity to the mother liquor is the first step to allow the stable mounting of a crystal. In previous work, we measured the equilibrium relative humidity for a range of concentrations of the most commonly used precipitants and showed how this related to Raoult’s law for the equilibrium vapour pressure of water above a solution. However, a discrepancy between measured values and those predicted by theory could not be explained. Here, we have used a more precise humidity control device to determine equilibrium relative humidity points. The new results are in agreement with Raoult’s law. We also present a simple argument in statistical mechanics demonstrating that the saturated vapour pressure of a solvent is proportional to its mole fraction in an ideal solution: Raoult’s Law. The same argument can be extended to the case where solvent and solute molecules are of different size, as is the case with polymers. The results provide a framework for the correct maintenance of the RH surrounding samples.SynopsisThe equilibrium relative humidity values for a number of the most commonly used precipitants in biological macromolecule crystallisation have been measured using a new humidity control device. A simple argument in statistical mechanics demonstrates that the saturated vapour pressure of a solvent is proportional to its mole fraction in an ideal solution (Raoult’s Law). The same argument can be extended to the case where solvent and solute molecules are of different size.

Cryoscopic and Viscosity Studies of Polyisobutylene. Cryoscopic Deviation of Polyisobutylene Solutions from Raoult's Law

1943 ◽  
Vol 16 (1) ◽  
pp. 69-84
Author(s):  
A. R. Kemp ◽  
H. Peters
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Infinite Dilution ◽  
Freezing Point ◽  
Raoult’S Law ◽  
Ideal Solutions ◽  
Chain Lengths ◽  
Selection Of ◽  
Raoult's Law

Abstract 1. The cryoscopic method is not satisfactory for polyisobutylenes having chain lengths much over 40 isobutylene units, on account of the failure of their solutions to obey Raoult's law. 2. The present work has led to the selection of a Kcm value of 0.75×104 for n-hexane solutions of polyisobutylene for use in the equation M=(log ηr×Kcm)/C. 3. Extrapolation of cryoscopic data obtained on nonideal solutions to infinite dilution gives inordinately high molecular weight values compared with those based on freezing point measurements of ideal solutions. 4. Of several solvents studied, n-hexane was found to be the best for viscosity—molecular weight measurements of polyisobutylene. 5. Fractionation of polyisobutylene by diffusion into mixtures of n-hexane and acetone resulted in the separation of the lower polymer fractions.

Vapour Pressure and Activity Coefficients of Dilute 2,2,4 Trimethylpentane(Isooctane)-Acetone Mixtures

1970 ◽  
Vol 25 (1) ◽  
pp. 45-47
Author(s):  
J. Edwards ◽  
M.V. Encina
Keyword(s):  
Activity Coefficients ◽  
Vapour Pressure ◽  
Pressure Measurements ◽  
Raoult’S Law ◽  
Azeotropic Point ◽  
Raoult's Law

Abstract Vapour pressure measurements are carried out to test Raoult's law at extreme concentrations, and the deviations are reported. - The azeotropic point is measured and qualitative discussions are presented.

scholarly journals Raoult's law revisited: accurately predicting equilibrium relative humidity points for humidity control experiments

2017 ◽  
Vol 50 (2) ◽  
pp. 631-638 ◽  
Author(s):  
Michael G. Bowler ◽  
David R. Bowler ◽  
Matthew W. Bowler
Keyword(s):  
Relative Humidity ◽  
Vapour Pressure ◽  
Important Variable ◽  
Control Device ◽  
Raoult’S Law ◽  
Simple Argument ◽  
Acta Cryst ◽  
Humidity Control ◽  
Humid Atmosphere ◽  
Raoult's Law

The humidity surrounding a sample is an important variable in scientific experiments. Biological samples in particular require not just a humid atmosphere but often a relative humidity (RH) that is in equilibrium with a stabilizing solution required to maintain the sample in the same state during measurements. The controlled dehydration of macromolecular crystals can lead to significant increases in crystal order, leading to higher diffraction quality. Devices that can accurately control the humidity surrounding crystals while monitoring diffraction have led to this technique being increasingly adopted, as the experiments become easier and more reproducible. Matching the RH to the mother liquor is the first step in allowing the stable mounting of a crystal. In previous work [Wheeler, Russi, Bowler & Bowler (2012). Acta Cryst. F68, 111–114], the equilibrium RHs were measured for a range of concentrations of the most commonly used precipitants in macromolecular crystallography and it was shown how these related to Raoult's law for the equilibrium vapour pressure of water above a solution. However, a discrepancy between the measured values and those predicted by theory could not be explained. Here, a more precise humidity control device has been used to determine equilibrium RH points. The new results are in agreement with Raoult's law. A simple argument in statistical mechanics is also presented, demonstrating that the equilibrium vapour pressure of a solvent is proportional to its mole fraction in an ideal solution: Raoult's law. The same argument can be extended to the case where the solvent and solute molecules are of different sizes, as is the case with polymers. The results provide a framework for the correct maintenance of the RH surrounding a sample.

Ideal Solutions and Colligative Properties

2021 ◽  
pp. 214-227
Author(s):  
Christopher O. Oriakhi
Keyword(s):  
Osmotic Pressure ◽  
Vapour Pressure ◽  
Boiling Point ◽  
Freezing Point ◽  
Freezing Point Depression ◽  
Pure Solvent ◽  
Ideal Solutions ◽  
Pressure Lowering ◽  
Colligative Properties

Ideal Solutions and Colligative Properties deals with the properties of solutions that depend on the concentration, but not the identity, of solute particles. The discussion examines the solution properties of vapour pressure depression, boiling point elevation, freezing point depression and osmotic pressure for an ideal solution, and how they differ from the properties of the pure solvent. Raoult’s law is used to quantify the magnitude of vapour pressure lowering. This is followed by illustrations of boiling point elevation and freezing point depression as well as the determination of boiling and freezing points of a solution. Calculation of osmotic pressure and its use to determine the molar mass of a solute is discussed.

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