Sodium carbonate dissociation

While this series of reactions is possible, much higher temperatures are required for sodium carbonate dissociation to sodium oxide and carbon... 

There are two serious problems associated with continuous tar distillation. Coal tar contains two types of components highly corrosive to ferrous metals. The ammonium salts, mainly ammonium chloride, associated with the entrained Hquor remain in the tar after dehydration, tend to dissociate with the production of hydrochloric acid and cause rapid deterioration of any part of the plant in which these vapors and steam are present above 240°C. Condensers on the dehydration column and fractionation columns are also attacked. This form of corrosion is controlled by the addition of alkaU (10% sodium carbonate solution or 40% caustic soda) to the cmde tar in an amount equivalent to the fixed ammonia content. 

Sodium chloride - table salt - is a strong ionic electrolyte because it dissociates fully when dissolved in water (see the discussion of weak and strong acids in Section 6.2). The only electrolytes in tonic water are sugar (which is not ionic) and sodium carbonate, which is a weak electrolyte, so very few ions are formed by adding the tonic water to a cell. 

By contrast, other substances—like the simple sugar glucose—do not dissociate at all and exist in solution as molecules held together by strong covalent bonds. There also are substances—like sodium carbonate (Na2C03)—that contain both ionic and covalent bonds. (See Figure 10-1.)... 

The sodium carbonate is a strong electrolyte and each formula unit dissociates completely to form 3 ions when placed in water. 

After administration, sodium bicarbonate dissociates to sodium and bicarbonate ions. With increased hydrogen ion concentrations bicarbonate ions combine with hydrogen ions to form carbonic acid, which then dissociates to COj, which is excreted by the lungs. 

Kust (4) has potentiometrically determined the equilibrium constant for carbonate dissociation in fused sodium-potassium nitrate eutectic ... 

AH° was found to be 27 kcal. and AS was 27 e.u. The large size of the constant compared with the known dissociation of pure sodium carbonate to sodium oxide and carbon dioxide suggests that NO4"3, or orthonitrate is probably formed when oxide ion is placed into fused nitrates. It may well be that the dissociation reaction for pure nitrate should be written ... 

The best way to spot Bronsted-Lowry acids and bases is to keep careful track of hydrogen ions in a chemical equation. Consider, for example, the dissociation of the base sodium carbonate in water. Note that although sodium carbonate is a base, it doesn t contain a hydroxide ion. 

To promote dissociation of the cellulose—CH,OH proton, dyeing is carried out in sodium carbonate solution with a pH around 10.6. The fraction of reactive cellulose is given by the fraction of dissociation of the weak acid at pH 10.6 ... 

The concentration of acidic groups can be determined by neutralization with a base, using solutions of sodium bicarbonate, sodium carbonate, sodium hydroxide or sodium ethoxide as titrants. Only those acidic groups which are much more strongly dissociated than the conjugate acids of the bases are completely neutralized. Thus, the differences in the amount of base required may be used to characterize the acidity of surface groups. Boehm (12) identified four different type of surface groups by this technique. 

The chemical category of inorganic salts encompasses many substances that dissociate completely in water, but only one salt, sodium chloride, is referred to by the common name, salt. Sodium chloride is ubiquitous in both its occurrence and its many uses. To date, there are over 14,000 uses for salt.1 Salt is used as a feedstock for many chemicals including chlorine, caustic soda (sodium hydroxide), synthetic soda ash (sodium carbonate), sodium chlorate, sodium sulfate, and metallic sodium. By indirect methods, sodium chloride is also used to produce hydrochloric acid and many other sodium salts. In its natural mineral form, salt may take on some color from some of the trace elements and other salts present, however, pure sodium chloride is a white to colorless crystalline substance, fairly soluble in water.2 Also known as halite, the substance... 

Now, proceed to calculate the fractional dissociation of the hydroxide ion from sodium carbonate. Begin by assuming a concentration for the carbonate of 0.1 M. This will then produce, also, 0.1 M of the carbonate ion. By its subsequent reaction with water, however, its concentration at equilibrium will be smaller. Let x be the concentrations of HCO, and OH" at equilibrium. Then the concentration of CO," is 0.1 - X (at equilibrium). Thus,... 

When heated to about 50°C, sodium bicarbonate begins to dissociate into carbon dioxide, sodium carbonate, and water on heating to 250-300°C, for a short time, sodium bicarbonate is completely converted into anhydrous sodium carbonate. However, the process is both time- and temperature-dependent, with conversion 90% complete within 75 minutes at 93°C. The reaction proceeds via surface-controlled kinetics when sodium bicarbonate crystals are heated for a short period of time, very fine needle-shaped crystals of anhydrous sodium carbonate are formed on the sodium bicarbonate surface. ... 

Derivation By the reduction of metal-nitrobenzene-sulfonic acid. Nitrobenzene is sulfonated until the product is soluble in water. The mixture is then poured into water and reduced with iron, made alkaline with lime, and the lime salt dissociated with sodium carbonate. 

TABLE 7.5 Carbon Dioxide Dissociation Pressures of Sodium Hydrogen Carbonate and Calcium and Sodium Carbonates"... 

The versatile mixture of sodium carbonate and sodium bicarbonate, on the other hand, finds widespread application, since the elution power and the selectivity resulting there from are determined over a wide range solely by the concentration ratio of these two compounds. A great variety of inorganic and organic anions can be separated with this eluent combination. As the product of the suppressor reaction, the carbonic acid is only weakly dissociated, so that the background conductivity is very low. 

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