751. The vapour pressure of the system sulphuric acid–disulphuric acid

1952 ◽  
Vol 0 (0) ◽  
pp. 3916-3922 ◽  
Author(s):  
J. C. D. Brand ◽  
A. Rutherford
Keyword(s):  
Sulphuric Acid ◽  
Vapour Pressure

scholarly journals Evaporation of sulphate aerosols at low relative humidity

2016 ◽  
Author(s):  
Georgios Tsagkogeorgas ◽  
Pontus Roldin ◽  
Jonathan Duplissy ◽  
Linda Rondo ◽  
Jasmin Tröstl ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Thermodynamic Properties ◽  
Sulphuric Acid ◽  
Activity Coefficients ◽  
Vapour Pressure ◽  
Equilibrium Constants ◽  
Cloud Chamber ◽  
Aerosol Dynamics ◽  
Sulphate Aerosols

Abstract. Here we explore the vapour pressure of sulphuric acid at very low relative humidity, where evaporation of sulphuric acid from particles can be important in the atmospheres of Earth and Venus. We performed experiments in the CLOUD chamber at CERN forming sulphuric acid particles via nucleation and then measuring evaporation versus temperature and relative humidity. We modelled the experiments with the ADCHAM model to constrain the thermodynamic properties governing the evaporation of sulphuric acid. ADCHAM includes a thermodynamics module coupled to an aerosol dynamics module. We derived the mole fractions and activity coefficients of H2SO4, HSO4−, SO42− and SO3 in the particles and then simulated the condensation and evaporation of H2SO4 and SO3. We constrained the equilibrium constants for the dissociation of H2SO4 to HSO4− (KH2SO4) and the dehydration of H2SO4 to SO3 (xKSO3). Our results suggest that particle shrinkage is mainly governed by H2SO4 evaporation, however, we cannot dismiss a contribution from SO3 evaporation. We conclude that KH2SO4 = 2–4 ∙ 109 mol ∙ kg−1 at 288.8 ± 5 K and xKSO3 ≥ 1.4 ∙ 1010.

Factors influencing the mode of thermal decomposition of zirconium sulphate tetrahydrate

1967 ◽  
Vol 20 (3) ◽  
pp. 415 ◽  
Author(s):  
IJ Bear
Keyword(s):  
Thermal Decomposition ◽  
Particle Size ◽  
Sulphuric Acid ◽  
Vapour Pressure ◽  
Thermal Decomposition Process ◽  
Monoclinic Zro2 ◽  
X Ray ◽  
Factors Influencing ◽  
Diffraction Patterns ◽  
Hydrolysis Of

The thermal decomposition process of zirconium sulphate tetrahydrate has been studied. Dehydration, which takes place via a crystalline monohydrate phase, is accompanied by the loss of small amounts of sulphuric acid apparently resulting from internal hydrolysis of the compound. This process gives a non-stoicheiometric zirconium sulphate which may exist in several modifications depending on the vapour pressure of the sulphuric acid around the sample during dehydration. The vapour pressure of the sulphuric acid is in turn controlled by such factors as the particle size of the tetrahydrate preparation, the size of sample, and the temperature and technique used during heating. Equilibration experiments have shown that a-Zr(SO4)2 is the stable anhydrous form. The X-ray powder diffraction patterns of a- and γ- Zr(SO4)2 have been indexed. Above 650� all forms of Zr(SO4)2 decompose to cubic ZrO2 which transforms to monoclinic ZrO2 at 800�.

scholarly journals Determination of vapour-pressure by air-bubbling

1905 ◽  
Vol 76 (508) ◽  
pp. 174-176
Keyword(s):  
Sulphuric Acid ◽  
Vapour Pressure ◽  
Considerable Degree ◽  
A Current

It was shown recently by one of us that the vapour-pressure of water can be determined with a considerable degree of accuracy by bubbling a current of air through water in a thermostat, and estimating the amount of water evaporated by absorbing it in strong sulphuric acid. The accuracy of the method has since been questioned, supersaturation being specially suggested as likely to cause error. We have therefore made experiments in order to discover what error (if any) is introduced by super­ saturating the air with moisture before it enters the water in the thermostat. The effect of dust in the air and of electrification have also been investigated. In each case the arrangement of the apparatus was as described in the previous paper.

A non-cyanide method of electropolishing silver

1978 ◽  
Vol 36 (1) ◽  
pp. 146-147
Author(s):  
R. L. Lyles ◽  
S. J. Rothman ◽  
W. Jäger
Keyword(s):  
Electron Microscopy ◽  
Sulphuric Acid ◽  
Methyl Alcohol ◽  
Health Hazards ◽  
Silver Alloy ◽  
High Quality ◽  
Silver Alloys ◽  
Free Sample ◽  
Specimen Quality ◽  
Standard Techniques

Standard techniques of electropolishing silver and silver alloys for electron microscopy in most instances have relied on various CN recipes. These methods have been characteristically unsatisfactory due to difficulties in obtaining large electron transparent areas, reproducible results, adequate solution lifetimes, and contamination free sample surfaces. In addition, there are the inherent health hazards associated with the use of CN solutions. Various attempts to develop noncyanic methods of electropolishing specimens for electron microscopy have not been successful in that the specimen quality problems encountered with the CN solutions have also existed in the previously proposed non-cyanic methods.The technique we describe allows us to jet polish high quality silver and silver alloy microscope specimens with consistant reproducibility and without the use of CN salts.The solution is similar to that suggested by Myschoyaev et al. It consists, in order of mixing, 115ml glacial actic acid (CH3CO2H, specific wt 1.04 g/ml), 43ml sulphuric acid (H2SO4, specific wt. g/ml), 350 ml anhydrous methyl alcohol, and 77 g thiourea (NH2CSNH2).

Sign in / Sign up

Export Citation Format

Share Document