Aqueous nonelectrolyte solutions. Part XVII. Formula of hydrogen sulfide hydrate and its dissociation thermodynamic functions

2000 ◽  
Vol 78 (9) ◽  
pp. 1204-1213 ◽  
Author(s):  
David N Glew
Keyword(s):  
Heat Capacity ◽  
Hydrogen Sulfide ◽  
Vapor Pressure ◽  
Standard Enthalpy ◽  
Approximate Formula ◽  
Saturation Vapor Pressure ◽  
Hydrate Dissociation ◽  
Quadruple Point ◽  
Heat Capacity Changes ◽  
Saturation Vapor

Literature data for the saturation vapor pressure P(hl1g) of hydrogen sulfide hydrate with water, at 43 temperatures between quadruple points Q(hs1l1g) at –0.4°C and Q(hl1l2g) at 29.484°C, are properly represented by a six-parameter equation to give a standard error (SE) of 0.13% on a hydrate pressure measurement of unit weight. Equilibrium hydrogen sulfide and water fugacities and the gas and aqueous phase compositions are derived using the Redlich–Kwong equation of state. Literature data for the saturation vapor pressure P(hs1g) of hydrogen sulfide hydrate with ice, at 15 temperatures between –1.249 and –21.083°C, are properly represented by a two-parameter equation to give a SE of 0.26% on a single hydrate pressure measurement. Quadruple point Q(hs1l1g) is evaluated at temperature –0.413° with SE 0.042°C and at pressure 94.7 with SE 0.26 kPa. Using the thermodynamic method, described for deuterium sulfide D-hydrate, the equilibrium fugacities of hydrogen sulfide are used to define 43 equilibrium constants Kp(h[Formula: see text]l1g) for hydrate dissociation into water and hydrogen sulfide gas. The temperature dependence of ln Kp(h[Formula: see text]l1g) is represented by a three-parameter thermodynamic equation which gives both values and standard errors (i) for Kp(h[Formula: see text]l1g), and for δHot(h[Formula: see text]l1g) and δCpot(h[Formula: see text]l1g), the standard enthalpy and heat capacity changes for hydrate dissociation and (ii) for n = r the approximate formula number of the hydrate H2S·nH2O at each experimental temperature. The formula H2S·6.119H2O with standard error 0.029H2O is found for hydrogen sulfide hydrate with water at lower quadruple point Q(hs1l1g) –0.413°C: an approximate formula H2S·5.869H2O with SE 0.026H2O is found at upper quadruple point Q(hl1l2g) 29.484°C. These estimates for the formula of hydrogen sulfide hydrate at its quadruple points are not significantly different from those found for the deuterium sulfide D-hydrate.Key words: clathrate hydrate of hydrogen sulfide, hydrogen sulfide hydrate, formula of hydrogen sulfide hydrate, thermodynamics of clathrate hydrate dissociation, dissociation equilibrium constant of hydrogen sulfide hydrate, standard enthalpy and heat capacity changes for dissociation of hydrogen sulfide hydrate.

Aqueous nonelectrolyte solutions. Part XVI. Formula of deuterium sulfide D-hydrate and its dissociation thermodynamic functions

2000 ◽  
Vol 78 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Colin W Clarke ◽  
David N Glew
Keyword(s):  
Heat Capacity ◽  
Thermodynamic Functions ◽  
Standard Enthalpy ◽  
Approximate Formula ◽  
Deuterium Oxide ◽  
Equilibrium Constants ◽  
Hydrate Dissociation ◽  
Quadruple Point ◽  
Dissociation Equilibrium ◽  
Heat Capacity Changes

A method has been devised to approximate both the hydrate formula number n and the standard thermodynamic functions for hydrate dissociation from the temperature change of the hydrate former fugacity along a univariant three-phase (hl1g) equilibrium line. Thermodynamic equations are derived, their validity discussed, and an iterative method for their solution is described. The univariant (hl1g) equilibrium dissociation of deuterium sulfide D-hydrate (D2S·nD2O phase h) into gaseous deuterium sulfide (g) and liquid deuterium oxide (l1) has been treated to give approximate formulae and dissociation constants at 58 temperatures from 2.798 to 30.666°C. Dissociation equilibrium constants Kp(h–> l1g) have been represented as a function of temperature by a four-parameter equation which yields both values and standard errors (i) for ΔHot(h–> l1g) and ΔCpot(h–> l1g) the standard enthalpy and heat capacity changes for D-hydrate dissociation and (ii) for n = r the approximate formula number of the D-hydrate at each experimental temperature. The formula D2S·6.115D2O with standard error 0.018D2O is found for deuterium sulfide D-hydrate at lower quadruple point Q(hs1l1g) 3.392°C; an approximate formula D2S·5.840D2O with SE 0.019D2O is found at upper quadruple point Q(hs1l2g) 30.770°C. Key words: clathrate D-hydrate of deuterium sulfide, deuterium sulfide D-hyfrate, formula of deuterium sulfide D-hydrate, thermodynamics of clathrate hydrate dissociation, dissociation equilibrium constant of deuterium sulfide D-hydrate, standard enthalpy, and heat capacity changes for dissociation of deuterium sulfide D-hydrate.

Aqueous nonelectrolyte solutions. Part XV. The deuterium sulfide - deuterium oxide system and the deuterium sulfide D-hydrate

1998 ◽  
Vol 76 (8) ◽  
pp. 1119-1129 ◽  
Author(s):  
Colin W Clarke ◽  
David N Glew
Keyword(s):  
Vapor Pressure ◽  
Gas Phase ◽  
Standard Error ◽  
Deuterium Oxide ◽  
Oxide System ◽  
Maximum Temperature ◽  
Saturation Vapor Pressure ◽  
Quadruple Point ◽  
Sulfide Phase ◽  
Saturation Vapor

The univariant (l1l2g) saturation vapor pressure of liquid deuterium oxide (phase l1) with liquid deuterium sulfide (phase l2) in equilibrium with a gas phase (g) has been measured in a stirred titanium reaction vessel at 19 temperatures from 33.003 to 18.905°C and at total pressures from 2.4500 to 1.7428 MPa. The univariant (hl1g) saturation vapor pressure of deuterium sulfide D-hydrate (phase h) in equilibrium with liquid deuterium oxide and a gas phase has been measured at 58 temperatures from 30.666 to 2.798°C and at pressures from 2.2959 to 0.11629 MPa. The maximum temperature for deuterium sulfide D-hydrate with a gas phase, the invariant quadruple point Q(hl1l2g), has been determined from the cut of the (hl1g) and the (l1l2g) curves at temperature 30.770°C with standard error 0.0043°C and at pressure 2.3263 MPa with standard error 0.00018 MPa. The univariant (s1l1g) equilibrium of D-ice (phase s1) with liquid deuterium oxide and a gas phase containing deuterium sulfide has been measured at 11 temperatures from 3.8061 to 3.4540°C and at pressures between 0.00242 and 0.10542 MPa. The lowest temperature for stability of deuterium sulfide D-hydrate with liquid deuterium oxide, the invariant quadruple point Q(hs1l1g), has been determined directly at 3.3917°C with standard error 0.0009°C and at pressure 0.12364 MPa with standard error 0.000011 MPa. This quadruple point Q(hs1l1g) has also been defined by the cut of the (hl1g) and the (s1l1g) curves at temperature 3.3912°C with standard error 0.0006°C and at pressure 0.12363 MPa with standard error 0.000002 MPa. The deuterium sulfide - deuterium oxide gas mixture, represented by a Redlich-Kwong equation of state, has been used to evaluate the fugacities and compositions of the gaseous and liquid deuterium oxide phases for all equilibria. Raoult's law using fugacities has been used to evaluate the saturation mole fraction of deuterium oxide in liquid deuterium sulfide and the Henry's law constant for deuterium oxide solubility in liquid deuterium sulfide between 33.003 and 18.905°C. Data for the (l1l2g) and (s1l1g) equilibria have been accurately represented by simple two-parameter equations. Data for the (hl1g) equilibrium have required a model with seven significant parameters for proper representation betweem 30.666 and 2.798°C.Key words: deuterium sulfide - deuterium oxide system, clathrate D-hydrate of deuterium sulfide, deuterium sulfide D-hydrate stability, freezing of deuterium oxide - deuterium sulfide, phase equilibria of deuterium sulfide - deuterium oxide.

Heat capacity, saturation vapor pressure, and thermodynamic functions of ethyl esters of C3–C5 and C18 carboxylic acids

2011 ◽  
Vol 85 (9) ◽  
pp. 1516-1527 ◽  
Author(s):  
L. E. Agafonova ◽  
R. M. Varushchenko ◽  
A. I. Druzhinina ◽  
O. V. Polyakova ◽  
Yu. S. Kolesov
Keyword(s):  
Heat Capacity ◽  
Vapor Pressure ◽  
Carboxylic Acids ◽  
Thermodynamic Functions ◽  
Ethyl Esters ◽  
Saturation Vapor Pressure ◽  
Saturation Vapor

The low-temperature heat capacity and saturation vapor pressure of ethyl ester of butanoic acid

2010 ◽  
Vol 65 (5) ◽  
pp. 285-294 ◽  
Author(s):  
L. E. Agafonova ◽  
A. I. Druzhinina ◽  
R. M. Varushchenko ◽  
O. V. Polyakova
Keyword(s):  
Heat Capacity ◽  
Low Temperature ◽  
Vapor Pressure ◽  
Ethyl Ester ◽  
Saturation Vapor Pressure ◽  
Butanoic Acid ◽  
Temperature Heat ◽  
Low Temperature Heat Capacity ◽  
Saturation Vapor

Thermal conductivity of R32 and R125 in the liquid phase at the saturation vapor pressure

1993 ◽  
Vol 14 (6) ◽  
pp. 1215-1220 ◽  
Author(s):  
M. Papadaki ◽  
W. A. Wakeham
Keyword(s):  
Thermal Conductivity ◽  
Liquid Phase ◽  
Vapor Pressure ◽  
Saturation Vapor Pressure ◽  
Saturation Vapor

scholarly journals Increased Accumulation On The Antarctic Ice Sheet Due To Climatic Warming

1990 ◽  
Vol 14 ◽  
pp. 361-361
Author(s):  
Stephen Warren ◽  
Susan Frankenstein
Keyword(s):  
Vapor Pressure ◽  
Sea Level ◽  
Ice Sheet ◽  
Crystal Formation ◽  
Climatic Warming ◽  
Saturation Vapor Pressure ◽  
Simple Assumption ◽  
Near Surface ◽  
The Antarctic ◽  
Saturation Vapor

Climatic warming due to increased greenhouse gases is expected to cause increased precipitation in the next century because of the increased water content of the air, assuming constant relative humidity. Since temperatures over most of Antarctica are far below freezing even in the warmest month of the year, the increase in melting is probably negligible compared to the increase in precipitation.Oerlemans (1982) showed that this increase of precipitation would cause a growth of the ice sheet, tending to lower sea level. This would partially counteract the rise of sea level due to increased melting on mountain glaciers and Greenland, and to a possible (and more difficult to predict) surge of ice from West Antarctica.Oerlemans may have underestimated the increase in accumulation. He used results of General Circulation Models (GCMs) which indicated an increase of precipitation by only 12% for a temperature change ΔΤ = 3 Κ and 30% for ΔΤ = 8 K. In contrast, the change in accumulation rate at Dome C (Lorius and others, 1979) accompanying the warming from the recent ice age to the present was in accord with the simple assumption that accumulation is proportional to saturation vapor pressure at the temperature of the inversion layer, i.e. a 30% increase for ΔΤ = 3 K.The experimental results are to be preferred to the climate model results because GCMs do not represent ice-sheet accumulation processes well. Most of the accumulation is not snow falling from clouds but instead results from clear-sky ice-crystal formation in near-surface air, or hoarfrost deposition on the surface. GCMs lack sufficient vertical resolution to represent the strong temperature inversion on which these accumulation mechanisms depend.The figure shows that the increase of vapor pressure due to ΔΤ = 5 Κ varies from a factor of 1.9 at Τ = −60°C to a factor of 1.6 at Τ = −20°C. A climatic warming of 5 K. over Antarctica, which is possible during the next century, could thus increase the Antarctic accumulation from its present 17g cm−2 yr−1 to 30 g cm−2 yr−1, leading to a 50 cm drop in sea level in 100 years. This assumes that the simple proportionality of precipitation rate to saturation vapor pressure applies as well to the coastal regions, which is doubtful because the accumulation processes are not the same as on the plateau.The potential importance of Antarctic accumulation changes in contributing to changes of sea level argues for further study of the mechanisms of Antarctic precipitation and for their improved representation in climate models.

scholarly journals Increased Accumulation On The Antarctic Ice Sheet Due To Climatic Warming

1990 ◽  
Vol 14 ◽  
pp. 361
Author(s):  
Stephen Warren ◽  
Susan Frankenstein
Keyword(s):  
Vapor Pressure ◽  
Sea Level ◽  
Ice Sheet ◽  
Crystal Formation ◽  
Climatic Warming ◽  
Saturation Vapor Pressure ◽  
Simple Assumption ◽  
Near Surface ◽  
The Antarctic ◽  
Saturation Vapor

Climatic warming due to increased greenhouse gases is expected to cause increased precipitation in the next century because of the increased water content of the air, assuming constant relative humidity. Since temperatures over most of Antarctica are far below freezing even in the warmest month of the year, the increase in melting is probably negligible compared to the increase in precipitation. Oerlemans (1982) showed that this increase of precipitation would cause a growth of the ice sheet, tending to lower sea level. This would partially counteract the rise of sea level due to increased melting on mountain glaciers and Greenland, and to a possible (and more difficult to predict) surge of ice from West Antarctica. Oerlemans may have underestimated the increase in accumulation. He used results of General Circulation Models (GCMs) which indicated an increase of precipitation by only 12% for a temperature change ΔΤ = 3 Κ and 30% for ΔΤ = 8 K. In contrast, the change in accumulation rate at Dome C (Lorius and others, 1979) accompanying the warming from the recent ice age to the present was in accord with the simple assumption that accumulation is proportional to saturation vapor pressure at the temperature of the inversion layer, i.e. a 30% increase for ΔΤ = 3 K. The experimental results are to be preferred to the climate model results because GCMs do not represent ice-sheet accumulation processes well. Most of the accumulation is not snow falling from clouds but instead results from clear-sky ice-crystal formation in near-surface air, or hoarfrost deposition on the surface. GCMs lack sufficient vertical resolution to represent the strong temperature inversion on which these accumulation mechanisms depend. The figure shows that the increase of vapor pressure due to ΔΤ = 5 Κ varies from a factor of 1.9 at Τ = −60°C to a factor of 1.6 at Τ = −20°C. A climatic warming of 5 K. over Antarctica, which is possible during the next century, could thus increase the Antarctic accumulation from its present 17g cm−2 yr−1 to 30 g cm−2 yr−1, leading to a 50 cm drop in sea level in 100 years. This assumes that the simple proportionality of precipitation rate to saturation vapor pressure applies as well to the coastal regions, which is doubtful because the accumulation processes are not the same as on the plateau. The potential importance of Antarctic accumulation changes in contributing to changes of sea level argues for further study of the mechanisms of Antarctic precipitation and for their improved representation in climate models.

ChemInform Abstract: SATURATION VAPOR PRESSURE OF NIOBIUM CHLORIDE (NBCL4) AND NIOBIUM BROMIDE (NBBR4)

1985 ◽  
Vol 16 (34) ◽  
Author(s):  
H. SCHAEFER ◽  
W. LOOSE ◽  
B. MONHEIM
Keyword(s):  
Vapor Pressure ◽  
Saturation Vapor Pressure ◽  
Niobium Chloride ◽  
Saturation Vapor
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