Chloride, mass-balance calculation

A simple use of mass-balance considerations that shows this net transformation of chlorinated ethenes is the observed accumulation of chloride in contaminant plumes. For example, in a study of a large plume of TCE-contaminated groundwater at Dover Air Force Base, Delaware, Witt et al. (2002) showed that the concentration of chloride increased as TCE concentrations decreased, suggesting the net transformation of the chlorine in TCE to chloride. This chloride tracer of chlorinated ethene biodegradation is of use for mass-balance calculations to demonstrate biodegradation processes in the held. These held observations formed the basis of experimental studies under controlled laboratory conditions that documented the many and varied microbial processes that transform and destroy chlorinated ethenes in groundwater systems. 

Fig. 14.18 Upper panel illustrates dissolved chloride concentration in pore waters collected from the summit of Hydrate Ridge during ODP leg 204 (Sites 1249, 1250, from Torres et al. 2004) and from a gravity core recovered from this area during RV SONNE expedition SO-143 (Haeckel et al. 2004). These data (panels A-C) indicate that hydrate is forming at very fast rates, so as to maintain the extremely high chloride values. Furthermore, to sustain the rapid formation rates, Torres et al. (2004) and Haeckel et al. (2004) show that methane must be supplied in the gas phase, as illustrated by the cartoon in panel. Methane solubility in seawater is too low for aqueous transport to deliver sufficient methane to form the observed hydrate deposits. D. Mass balance calculations based on a simple box model (E) indicate that the massive deposits recovered from the Hydrate Ridge summit probably formed in a period of the order of lOO s to lOOO s of years, highlighting the dynamic nature of these near-surface deposits (modified from Torres et al. 2004 and Haeckel et al. 2004).

The scaling tendency of the lime or limestone processes for flue gas desulfurization is highly dependent upon the supersaturation ratios of calcium sulfate and calcium sulfite, particularly calcium sulfate. The supersaturation ratios cannot be measured directly. They are determined by measuring experimentally the molalities of dissolved sulfur dioxide, sulfate, carbon dioxide, chloride, sodium and potassium, calcium, magnesium, and pH. Then by calculation, the appropriate activities are determined, and the supersaturation ratio is determined. Using the method outlined in Section IV, the concentrations of all ions and ion-pairs can be readily determined. The search variables are the molalities of bisulfite, bicarbonate, calcium, magnesium, and sulfate ions. The objective function is defined from the mass balance expressions for dissolved sulfur dioxide, sulfate, carbon dioxide, calcium, and magnesium. This equation is... 

Excluding activity coefficients, three relationships are required in addition to the nine thermodynamic equilibria in order to calculate concentrations of the 12 unknown species. These relationships are the mass balances for magnesium and chloride, and the electroneutrality equation. 

Practice Problem 10.7 The industrial process for the production of sodium metal and chlorine gas involves electrolysis of molten (melted) sodium chloride (in the absence of water). Calculate the mass of sodium that can be prepared by electrolysis of 207 kg of sodium chloride. The balanced equation is... 

The number of particles is a function of emulsifier type and concentration and initiator level, although for monomers that obey Case 1 kinetics such as vinyl chloride and vinyl acetate, is almost independent of initiator level (Ugelstad et al, 1969 Friis and Nyhagen, 1973). The calculation of iVp for various reactor operations will he discussed later. The monomer concentration in the polymer particle [Mp] can he obtained using a simple mass balance. Assuming the monomer and pdymer volumes are additive, one obtains the following relationship for the conversion interval,... 

Dissolution of feldspars is a logical source of dissolved silica, calcium, sodium, and potassium in groundwater. Similarly, the reaction of carbon dioxide-charged water with silicate minerals is a logical source of bicarbonate. Rogers (1987) examined these and other hypotheses using a mass-balance approach. In these calculations, chloride and sulfate were not considered, and the beginning concentrations were considered to be... 

It is useful to construct diagrams that show changes in the relative importance of complexes as a function of pH or the concentration of a metal or ligand. In such a problem, Butler (1964) describes how to calculate as a function of uncomplexed chloride ion, (Cl ), the fraction of Cd present as Cd ion and as the several Cd-Cl complexes. The general approach involves defining and solving simultaneously a series of equilibria, mass-balance, and charge-balance equations. 

Thus determination of the partition coefficient for any easily measured ionic solute can be used to calculate the Ionic content of the gel. Ionic dyes like methyl orange are especially attractive test solutes because they are easily and accurately measured spectrophotometrically at low concentrations. However any ionic solute can be used, including simple salts like sodium chloride. To carry out this experiment, the water swollen gel is immersed in a roughly equal volume of a dilute solution containing the test solute. From the change in solution concentration as solute diffuses into the gel, can be determined by a mass balance. The inherent effectiveness of this technique using variety of test solutes Is clearly evident in the work of Gehrke et al. [4]. 

When potassium chlorate is heated, it decomposes to produce potassium chloride and oxygen gas. Write a balanced equation for this reaction, and calculate the mass of potassium chlorate needed to produce 5.00 X 10 mL of oxygen gas at 1.108 atm and 39°C. 

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