C. R. Fuget

Bio: C. R. Fuget is an academic researcher. The author has contributed to research in topics: Aqueous solution & Boiling point. The author has an hindex of 1, co-authored 1 publications receiving 52 citations.

Thermodynamics and Kinetics of the Solid Solution of HCl in Ice

Abstract: The equilibrium solubility of HCl in ice Ih has been measured as a function of temperature and HCl partial pressure, between −8 and −35 °C by doping large ice single crystals with gaseous HCl for several weeks. Results indicate that the solubility of HCl in ice is very low, much less than found in many previous studies. Its temperature and HCl partial pressure dependences are found to be XHCl = 6.13 × 10-10e2806.5/T (PHCl)1/2.73 where XHCl is the solubility in mole fraction, PHCl is the HCl partial pressure in Pa, and T is the temperature in kelvin. The diffusion coefficient of HCl in ice is also found to be very low, about 10-12 cm2/s at −15 °C. Extrapolations of these data yield the solidus in the temperature−composition phase diagram. The determination of the solid phase composition in equilibrium with a given gas phase composition allows the calculation of the partial enthalpy of sublimation of HCl from ice, Δ = 63.7 ± 7.6 kJ/mol, and of the activity of HCl in ice. Possible mechanisms of HCl incorpora...

A model for studying the composition and chemical effects of stratospheric aerosols

Abstract: We developed polynomial expressions for the temperature dependence of the mean binary and water activity coefficients for H2SO4 and HNO3 solutions. These activities were used in an equilibrium model to predict the composition of stratospheric aerosols under a wide range of environmental conditions. For typical concentrations of H2O, H2SO4, HNO3, HCl, HBr, HF, and HOCl in the lower stratosphere, the aerosol composition is estimated as a function of the local temperature and the ambient relative humidity. For temperatures below 200 K, our results indicate that (1) HNO3 contributes a significant mass fraction to stratospheric aerosols, and (2) HCl solubility is considerably affected by HNO3 dissolution into sulfate aerosols. We also show that, in volcanically disturbed periods, changes in stratospheric aerosol composition can significantly alter the microphysics that leads to the formation of polar stratospheric clouds. The effects caused by HNO3 dissolution on the physical and chemical properties of stratospheric aerosols are discussed.

The solubility and behaviour of acid gases in the marine aerosol

Abstract: The following Henry's law constants (K H/mol2kg-2atm-1) for HNO3 and the hydrohalic acids have been evaluated from available partial pressure and other thermodynamic data from 0°–40°C, 1 atm total pressure: HNO 3 , 40°C–5.85×105; 30°C–1.50×106; 25°C–2.45×106; 20°C–4.04×106; 10°C–1.15×107; 0°C–3.41×107. HF, 40°C–3.2; 30°C–6.6; 25°C–9.61; 20°C–14.0; 10°C–32.0; 0°C–76. HCl, 40°C–4.66×105; 30°C–1.23×106; 25°C–2.04×106; 20°C–3.37×106; 10°C–9.71×106; 0°C–2.95×107. HBr, 40°C–2.5×108; 30°C–7.5×108; 25°C–1.32×109; 20°C–2.37×109; 10°C–8.10×109; 0°C–3.0×1010. HI, 40°C–5.2×108; 30°C–1.5×109; 25°C–2.5×109; 20°C–4.5×109; 10°C–1.5×1010; 0°C–5.0×1010. Simple equilibrium models suggest that HNO3, CH3SO3H and other acids up to 10x less soluble than HCl displace it from marine seasalt aerosols. HF is displaced preferentially to HCl by dissolved acidity at all relative humidities greater than about 80%, and should be entirely depleted in aged marine aerosols.

Interaction of HCl vapor with water-ice: Implications for the stratosphere

Abstract: The nature of the interaction of HCl vapor with ice has been investigated, using thermal analysis and FTIR spectroscopy to characterize the ice substrate, and mass spectrometry to measure the concentration of HCl and H{sub 2}O vapors in the gas phase. The results indicate that a liquid layer is formed rapidly at the ice surface for ice exposed to HCl vapor at partial pressures above those characteristic of the ice-liquid (aqueous HCl solution) equilibrium system. This liquid layer also forms below the eutectic temperature (186 K); that is, it forms even at temperatures at which the liquid is metastable with respect to the formation of HCl trihydrate. For smaller HCl partial pressures such as those prevailing in the stratosphere, the HCl is taken up by the ice surface in amounts corresponding to a large fraction of a monolayer. The chemical reactivity of this surface HCl is very large: Chlorine activation by type II polar stratospheric clouds (consisting of ice particles) should occur efficiently by reaction of the HCl with ClONO{sub 2}. 31 refs., 9 figs.