Carbon dioxide calculated partial pressures

When the equations are applicable, the affinity between solids and gases can be calculated very simply. As was explained on p. 316, it is sufficient for this purpose to calculate the work which can be obtained by making the reaction take place in any reversible manner. Thus the affinity between calcium oxide and gaseous carbon dioxide at partial pressure P can be calculated as follows. Let the carbon dioxide be compressed or expanded reversibly at the temperature T for which we wish to calculate the affinity, until its pressure is equal to the partial pressure p which is in equilibrium with solid CaO and CaCOg at this temperature. The work obtained in this process is P... 

At 2500 K and 1 atm pressure the observed density of COg gas is 0.1991 g/i. What is the average molecular weight of the molecules in the gas Assuming that the molecular weight is decreased because the carbon dioxide has partially decomposed into carbon monoxide and oxygen, calculate what fraction of the CO2 molecules have decomposed in this way. 

Given that the partial pressure of carbon dioxide in the troposphere is 0.26 Torr and that the temperature is 25°C, calculate the volume of air needed to produce 10.0 g of glucose. 

Atmospheric O2 has a partial pressure of 0.20 bar, and atmospheric water vapor is saturated with carbon dioxide. This dissolved CO2 forms carbonic acid, which generates a hydronium ion concentration of about 2.0 X 10 M. The Nemst equation allows calculation of the half-cell potential for the reduction of 02(g) under these... 

As explained in the previous section, the P02 of the atmosphere is 160 mmHg. The partial pressure of carbon dioxide (PC02) is negligible (see Table 17.1). As air is inspired, it is warmed and humidified as it flows through the conducting airways. Therefore, water vapor is added to the gas mixture. This is accounted for in the calculation of P02 in the conducting airways ... 

Fig. 4.2 Comparison of amino acid yields using CH4, CO and CO2 as carbon sources with the addition of varying amounts of H2. The yields were calculated on the basis of the amount of carbon present in the reaction mixture. In all cases, the partial pressures of nitrogen, methane, carbon monoxide and carbon dioxide were lOOmmHg. For the reactions using nitrogen, the reaction vessel contained 100 mL of water, but no ammonia. Reactions involving nitrogen and ammonia were carried out using 100 mL of ammonium chloride (0.05 M). The electrical discharge experiments took 48 hours at room temperature (Schlesinger and Miller, 1983)...

Carbon dioxide plays a key role in climate, in biological processes, in weathering reactions, and in marine chemistry. I shall next describe how the partial pressure of this gas in the atmosphere may be calculated. Because there is a rapid exchange of carbon dioxide between ocean and atmosphere, we must consider the fate of dissolved carbon. 

In order to calculate the partial pressure of carbon dioxide, it is necessary to figure the total dissolved carbon and alkalinity as well. I consider three reservoirs—atmosphere, surface sea, and deep sea—as illustrated in Figure 5-1. I distinguish between the concentrations in the surface and deep reservoirs by using a terminal letter. v for the surface reservoir and d for the deep reservoir. 

The difference between the total dissolved carbon in the surface and in deep-sea reservoirs depends on productivity. And the difference between the alkalinity in these reservoirs depends on productivity and also corat, the calcium-carbonate-to-organic-carbon ratio. The carbon dioxide partial pressure depends on the difference between total carbon and alkalinity in the surface reservoir, and all these depend on the total amount of carbon and alkalinity at the start of the calculation in the three reservoirs combined. By adjusting the values of these various parameters and repeating the calculation, I arrive at the following values for a steady-state system that is close to the present-day ocean with a preindustrial level of atmospheric carbon dioxide ... 

Cardiac arrest IV Initially, 1 mEq/kg (as 7.5%-8.4% solution). May repeat with 0.5 mEq/kg qlOmin during continued cardiopulmonary arrest. Use in the postresuscitation phase is based on arterial blood pH, partial pressure of carbon dioxide in arterial blood (PaCOj) and base deficit calculation. 

The dew point of the gas depends on the gas pressure and the carbon dioxide partial pressure. At fixed carbon dioxide composition, the dew point is lowered as total pressure decreases at fixed total pressure, the dew point is lowered as carbon dioxide composition decreases. Calculated dew points for a synthesis gas with 30 mol % carbon dioxide, for both ideal and real gas behavior, are shown in Figure 3 for syn gas pressures up to 1500 psia. 

The above expression can be used to determine [H+] for any given partial pressure pC02(g) of carbon dioxide. Thus, for an atmosphere with a partial pressure of C02 of 0.00033, [H+] can be calculated to be 2.24 X 10 6moldm 3 which gives a pH of 5.65. 

There is an abundance of experimental gas partial pressures for gas hydrate equilibria across a broad range of temperatures (Fig. 3.10 Sloan 1998). The lower temperature limit in our model database for these systems is 180 K (Fig. 3.10) because this is the lower limit of our model s ability to estimate aw (Fig. 3.1, Eq. 3.11), which is needed to calculate the solubility product of gas hydrates (Eq. 3.36). In our model, the upper temperature limit for methane hydrate is at 298 K (25 °C), which is the upper temperature limit for FREZCHEM the upper temperature limit for carbon dioxide hydrate is at 283K (10 °C), which is the temperature where liquid C02(l) becomes the thermodynamically stable phase. 

Before proceeding, a few general comments will be helpful. In most cases at least one of the four carbonate system analytical quantities (total alkalinity, total CO2, carbon dioxide partial pressure, and pH) will be known. The equilibrium equations relating these quantities, along with those for water and calcite, will be used frequently in calculations. Also, in cases where calcite dissolution and... 

The Bunsen absorption coefficient of carbon dioxide in water at 20°C is 0.88. Calculate the solubility of carbon dioxide in water at 20°C and a partial pressure of carbon dioxide of 0.54 atm. 

Whether corrosive constituents are removed at the oil or gas well or just before they enter cross country lines is a matter of economics (i.e., cost of the line, ease of replacement, etc). When dehydration or gas purification is not performed at the wellhead, severe corrosion may occur. Laboratory data on the corrosion rate vs partial pressure of carbon dioxide (Figure 4.5 in Chapter Four) often do not give a good estimate of the corrosiveness of the fluid because variables other than carbon dioxide partial pressure also affect metal loss. When the gas contains less than 15% oil (corrosion is low when there is more than 15% oil in the gas) and velocities are high, the chemical composition of the water, rather than the carbon dioxide partial pressure, appears to control the corrosion. The pH of the system calculated from the water composition has been used to determine whether or not a well is corrosive. To date, however, there is not a one-to-one correlation between the in situ pH and corrosiveness. 

Figure 5-21 shows computed values of the spectral emissivity eg = 8 x(T,pL,X) as a function of wavelength for an equimolar mixture of carbon dioxide and water vapor for a gas temperature of 1500 K, partial pressure of 0.18 atm, and a path length L = 2 m. Three principal absorption-emission bands for C02 are seen to be centered on 2.7, 4.3, and 15 pm. Two weaker bands at 2 and 9.7 pm are also evident. Three principal absorption-emission bands for water vapor are also identified near 2.7, 6.6, and 20 pm with lesser bands at 1.17, 1.36, and 1.87 pm. The total emissivity eg and absorptivity a 1 are calculated by integration with respect to wavelength of the spectral emissivities, using Eqs. (5-138) in a manner similar to the development of total surface properties. 

In both cases the empirical constants are given for the three temperatures of 1000,1500, and 2000 K. Table 5-5 also includes some six values for the partial pressure ratios pw/pc of water vapor to carbon dioxide, namely 0, 0.5, 1.0, 2.0,3.0, and . These ratios correspond to composition values of pc / (pc + pw) =1/(1+ pw tyc) of 0, 1/3, 1/2, 2/3, 3/4, and unity. For emissivity calculations at other temperatures and mixture compositions, linear interpolation of the constants is recommended. 

Carbonate iron sediments are formed when iron is precipitated in the presence of dissolved carbonic acid or as a result of interaction of the primary sediments with organic matter in the course of diagenesis. The determination of the stability of primary iron carbonates with respect to iron oxides and hydroxides was made on the basis of using the functional dependence of and on pH, calculated by the method of Garrels and Christ (1968) for the system carbonate-water. According to this dependence, in conditions of FeCOj in equilibrium with water the value of partial pressure of carbon dioxide decreases in proportion to increasing pH. 

A material balance must also be made on the carbon dioxide in the gas phase to calculate the partial pressure of carbon dioxide for use in Henrys law. This is given (assuming complete mixing) in Equation 29. 

Reactivity profiles were measured vs. conversion over a broad range of temperatures and carbon dioxide partial pressures for all three chars. A reference reactivity profile was chosen and used to eliminate the structural profile in the relevant experiments. Kinetic parameters are calculated by using both the normalised reactivity (ff ) and the reactivity at 20, 40. 60 and 80% conversion Rx20> l x4 Rxm and Rx8o)-Calculated reactivities are compared. 

Figure 1. Henry s constants of gases in binary solvent mixtures at 760 mmHg partial pressure ( , experimental A, calculated with the new eq 25 B, calculated with Krichevsky eq 1 in Figure la, C represents eq A2-3) (a) oxygen (2) in 1-propanol (1)—water (3) at 40 °C, (b) nitrogen (2) in 2-propanol (l)-water (3) at 40 °C, (c) oxygen (2) in ethanol (l)-water (3) at 40 °C, and (d) carbon dioxide (2) in 1-propanol (l)-water (3) at 40 °C. Xaic is the mole fraction of the alcohol in the gas-free mixture of solvents.

Air contains oxygen (O2), nitrogen (N2), carbon dioxide (CO2), and trace amounts of other gases. Use the known pressures in Table 2 to calculate the partial pressure of oxygen. 

Equation 2.78 predicts that the rate of SRM reaction can be determined mainly by the partial pressure of methanol. For water, the rate shows a weak reverse dependence. The adsorption of carbon dioxide is competitive to that of methanol, water, and the oxygenate intermediates and thereby inhibiting the overall reaction. The apparent activation energy calculated based on these kinetic studies for various Cu-based catalysts are in the range between 70 and 90kJ/mol. The rate expressions and activation energies for the SRM reaction over a few Cu-based catalysts reported in the recent literature are summarized in Table 2.25.188,210-213... 

Figure 46-10 Partial pressures of oxygen and carbon dioxide in air, blood, and tissue. Values shown are approximations in mm Hg and calculated assuming a 5% shunt. Heavy arrows show directions of gradients. (Modified from Tietz NW. Fundamentals of clinical chemistry, 3rd ed. Philadelpbla WB Saunders Co, 1987.)...

Fig. 10. Undersaturation of the partial CO2 pressure, comparison between sink (10) and karst (13) water — sampled month to month (A—R) and week to week (1—8). The variation of the carbon dioxide undersaturation is entirely identical between the different data points (for calculation of the carbon dioxide undersaturation, see explanation in the text).

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