Gases, dissolved water

The apparatus is sometimes referred to as an oxygen electrode , but it is actually a cell. Although the Teflon membrane is impermeable to water and, therefore, to most substances dissolved in water, dissolved gases can pass through, and gases, such as chlorine, sulphur dioxide and hydrogen sulphide, can affect the electrode. The apparatus can be made readily portable and it is, therefore, of value for use in the field and can be used to monitor the oxygen content of rivers and lakes (see Ref. 53). 

Sulphur dioxide, SO2, m.p. — 72-7°C, b.p. — I0"C. Colourless gas with characteristic smell. Formed by burning S, metal sulphides, H2S in air or acid on a sulphite or hydrogen sulphite. Powerful reducing agent, particularly in water. Dissolves in water to give a gas hydrate the solution behaves as an acid - see sulphurous acid. Used in the production of SO3 for sulphuric acid. 

The value of the compresjiibility of oil is a function of the amount of dissolved gas, but is in the order of 10 x 10" psi" By comparison, typical water and gas compressibilities are 4x10" psi" and 500 x 10" psi" respectively. Above the bubble point in an oil reservoir the compressibility of the oil is a major determinant of how the pressure declines for a given change in volume (brought about by a withdrawal of reservoir fluid during production). 

Formation water density is a function of its salinity (which ranges from 0 to 300,000 ppm), amount of dissolved gas, and the reservoir temperature and pressure. As pressure increases, so does water density, though the compressibility is small... 

The formation volume factor for water (B, reservoir volume per stock tank volume), is close to unity (typically between 1.00 and 1.07 rb/stb, depending on amount of dissolved gas, and reservoir conditions), and is greater than unity due to the thermal contraction and evolution of gas from reservoir to stock tank conditions. 

Why is potassium aluminium sulphate not soluble in benzene A compound M has the composition C = 50.0% H=12.5%o A1 = 37.5%. 0.360 g of M reacts with an excess of water to evolve 0.336 1 of gas N and leave a white gelatinous precipitate R. R dissolves in aqueous sodium hydroxide and in hydrochloric acid. 20 cm of N require 40 cm of oxygen for complete combustion, carbon dioxide and water being the only products. Identify compounds N and R, suggest a structural formula for M, and write an equation for the reaction of M with water. (All gas volumes were measured at s.t.p.)... 

It should be noted that the highest possible absorption rates will occur under conditions in which the hquid-phase resistance is negligible and the equilibrium back pressure of the gas over the solvent is zero. Such situations would exist, for instance, for NH3 absorption into an acid solution, for SO9 absorption into an alkali solution, for vaporization of water into air, and for H9S absorption from a dilute-gas stream into a strong alkali solution, provided there is a large excess of reagent in solution to consume all the dissolved gas. This is known as the gas-phase mass-transfer limited condition, wrien both the hquid-phase resistance and the back pressure of the gas equal zero. Even when the reaction is sufficiently reversible to allow a small back pres-... 

The primary source of noncondensable gases usually is air dissolved in the condenser water. Figure 11-126 shows the dissolved-gas content of fresh water and seawater, calculated as equivalent air. The... 

Liquid/Solid Mass Transfer The dissolved gas and the solvent react in contact with the surface of the catalyst. For studying the rate of transfer to the surface, an often-used system was benzoic acid or naphthalene in contact with water. A correlation of Dharwadkar and Sylvester (AJChE Journal, 23, 376 [1977]) that agrees well with some others is... 

It is shown that metrological characteristics of the suggested methods are commensurable. Dissolved gas is pushed away by front of crystallization, takes the air and does not influence on the obtained results during the analysis of the water. Process is carried out at the lower temperature (-15°C), expelling chemical transformations of ingredients. The procedure was tested on different samples of natural and drinking water of the Kharkov region. 

Sources of air or inerts include dissolved gas in the cooling water in case of jet condensers, entrainment with steam, entrainment with vapor, leaks, and noncondensable gases. 

Chemical Reactivity - Reactivity with Water Dissolves and forms a weak solution of hydrofluoric acid Reactivity with Common Materials In presence of moisture will corrode glass, cement and most metals. Flammable hydrogen gas may collect in enclosed spaces Stability During Transport Stable Neutralizing Agents for Acids and Caustics Flush with water, rinse with dilute solution of sodium of sodium bicarbonate or soda ash Polymerization Not pertinent Inhibitor of Polymerization Not pertinent. 

Chlorine is a member of the halogen (salt-forming) group of elements and is derived from chlorides by the action of oxidizing agents and, most frequently, by electrolysis. As a gas, it combines directly with nearly all elements. At 10 C, 1 volume of water dissolves about 3.10 volumes of chlorine at 30 C, only 1.77 volumes of CI2 are dissolved in 1 volume of water. 

H28 is readily soluble in both acidic and alkaline aqueous solutions. Pure water dissolves 4.65 volumes of the gas at 0° and 2.61 volumes at 20° in other units a saturated solution is 0.1 M at atmospheric pressure and 25°, i.e. 

Oil production requires pressure from compressed gas or water to expel oil to the surface. There arc three main types of rcsci voir drives to flush oil to wells dissolved gas drive, gas-cap drive, and water drive. With a gas drive, the oil in the reservoir is saturated with dissolved gas. As pressures fall with oil production, the gas escapes from solution, expands, and propels oil to the surface. Hence it is important to control gas production so it remains available to remove the oil. With a gas-cap drive, the upper part of the reseiwoh is filled with gas, and oil lies beneath it. As oil is withdrawn, the compressed gas expands downward, pushing oil to the well bore. As with a dissolved gas drive, gas production from the gas cap should be restricted to maintain reservoir pressure to expel the oil. Finally, with a water drive, the oil lies above a layer of water. The compressed water... 

Note that from Table 4-128 the very large volumes that can dissolve in oil-base muds. For the water-base muds, 0.6 to 0.9% of gas will dissolve and not appreciably change the density or compressibility of the mud. It will be difficult to detect these low concentrations with downhole physical measurements. Free gas will be easily detected as shown hereafter. For the oil-base muds we will assume no free gas is present at bottomhole and the mud properties are changed only due to the dissolved gas. The detection will be more difficult than with free gas. 

Table 4-128 shows maximum dissolved gas concentrations in drilling muds at the bottom of the hole. Figure 4-264 shows the variation of the acoustic velocity for two water-base muds and two oil-base muds of 9 and 18 Ib/gal at pressures of 5,000 and 10,000 psi. 

Deviations from Henry s law are exhibited by most gases having absorption coefficients greater than 100. In some cases the discrepancies vanish at higher temperatures. Thus Roscoe and Dittmar (1860) found that ammonia did not follow the law of Henry at the ordinary temperature, but Sims (1862) showed that the deviations from the law became less as the temperature at which absorption occurred increased, until at 100° the amount of ammonia dissolved by water was directly proportional to the pressure. The deviations appear to be always greatest under small pressures, and to decrease with increasing pressure, and therefore with increasing concentration of the solution they are doubtless due to chemical interaction between the solvent and dissolved gas. 

Domestic heating coil internal corrosion. Where naturally soft or lean city water is supplied and the Langelier Saturation Index (LSI) is below -1.0, acid corrosion takes place as a result of the acidic nature of the water. This water often has a high dissolved gas content, which additionally leads to pinhole corrosion. Where water velocities are too high (say, over 6 ft/s 1.8 m/s) the protective oxide layer is stripped off and erosion corrosion takes place. 

Almost all aquatic organisms rely on the presence of dissolved oxygen for respiration. Although oxygen is nonpolar, it is very slightly soluble in water and the extent to which it dissolves depends on its pressure. We have already seen (in Section 4.2) that the pressure of a gas arises from the impacts of its molecules. When a gas is introduced into the same container as a liquid, the gas molecules can burrow into the liquid like meteorites plunging into the ocean. Because the number of impacts increases as the pressure of a gas increases, we should expect the solubility of the gas—its molar concentration when the dissolved gas is in dynamic equilibrium with the free gas—to increase as its pressure increases. If the gas above the liquid is a mixture (like air), then the solubility of each component depends on that component s partial pressure (Fig. 8.21). 

Using the properties of water Li and Cheng (2004) computed from the classical kinetics of nucleation the homogeneous nucleation temperature and the critical nu-cleation radius ra. The values are 7s,b = 303.7 °C and r nt = 3.5 nm. However, the nucleation temperatures of water in heat transfer experiments in micro-channels carried out by Qu and Mudawar (2002), and Hetsroni et al. (2002b, 2003, 2005) were considerably less that the homogeneous nucleation temperature of 7s,b = 303.7 °C. The nucleation temperature of a liquid may be considerably decreased because of the following effects dissolved gas in liquid, existence of corners in a micro-channel, surface roughness. 

Carbonated beverages illustrate what happens when a dissolved gas undergoes a rapid drop in pressure. Soft drinks, soda water, and champagne are bottled under several atmospheres pressure of carbon dioxide. When a bottle is opened, the total pressure quickly falls to 1 atm. At this lower pressure, the concentration of CO2 in the solution is much higher than its solubility, so the excess CO2 forms gas bubbles and escapes from the liquid. As the photo shows, this process can be dramatic. 

Gel-like soft crystals, which form in the bulk of liquid water at a defl-ciency of dissolved gas in water... 

Solutions Solutions are homogeneous forms of matter that may be composed of a solid dissolved in a liquid - such as common salt dissolved in water a gas dissolved in a liquid - for example, oxygen dissolved in water or a solid dissolved in another - for example, carbon dissolved in iron in some alloys of this metal. The composition and properties of each solution are determined by the nature of the components and the relative amount of each component in the solution (see Table 2). 

It is widely considered that the physical properties of dissolved gases affect the sonochemical efficiency. The ratio of specific heats, y = Cp/Cv, the thermal conductivity, and the solubility in water are the important parameters. The effects of dissolved gas on the reduction of Au(III) under ultrasonic irradiation are shown in Fig. 5.6 [29]. It can be seen that the changes in the concentration of Au(III) are strongly dependent on the types of dissolved gas. 

Table 8.3. Notice how the polar solvent water supports significantly more dissolved gas than the non-polar solvent. However, gases dissolved in solutions go on to produce other compounds, most importantly protons, that determine the ocean pH or the pH of Darwin s little warm pool .

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