Calcium hydroxide Table

To prepare the standard pH buffer solutions recommended by the National Bureau of Standards (U.S.), the indicated weights of the pure materials in Table 8.15 should be dissolved in water of specific conductivity not greater than 5 micromhos. The tartrate, phthalate, and phosphates can be dried for 2 h at 100°C before use. Potassium tetroxalate and calcium hydroxide need not be dried. Fresh-looking crystals of borax should be used. Before use, excess solid potassium hydrogen tartrate and calcium hydroxide must be removed. Buffer solutions pH 6 or above should be stored in plastic containers and should be protected from carbon doxide with soda-lime traps. The solutions should be replaced within 2 to 3 weeks, or sooner if formation of mold is noticed. A crystal of thymol may be added as a preservative. 

Excess calcium hydroxide is precipitated by usiag carbon dioxide and the calcium carbonate, calcium hydroxide, and calcium phosphite are removed by filtration. The filtered solution is treated with an equivalent amount of sodium sulfate or sodium carbonate to precipitate calcium sulfate or carbonate. Sodium hypophosphite monohydrate [10039-56-2] is recovered upon concentration of the solution. Phosphinic acid is produced from the sodium salt by ion exchange (qv). The acid is sold as a 50 wt %, 30—32 wt %, or 10 wt % solution. The 30—32 wt % solution is sold as USP grade (Table 12) (63). Phosphinic acid and its salts are strong reduciag agents, especially ia alkaline solution (65). 

While pure chlorine gas will certainly bleach colors, laundry bleaches use sodium hypochlorite or calcium hypochlorite, which works by releasing oxygen, not chlorine. The chlorine remains in solution, either as sodium chloride (table salt), or calcium chloride. These bleaches are made by bubbling chlorine gas through a solution of sodium hydroxide (lye) or calcium hydroxide (quicklime). 

Table 9.7. Composition of a calcium hydroxide chelate cement American Dental Association, 1977)...

All commercial materials are based on calcium hydroxide and liquid alkyl salicylates (Prosser, Grolfman Wilson, 1982) and are supplied as a two-paste pack. Zinc oxide is sometimes added to the calcium hydroxide, as are neutral fillers. A paste is formed from this powder by the addition of a plasticizer examples include A-ethyl toluenesulphonamide (o- orp-) and paraffin oil, with sometimes minor additions of polypropylene glycol. The other paste is based on an alkyl salicylate as the active constituent containing an inorganic filler such as titanium dioxide, calcium sulphate, calcium tungstate or barium sulphate. Alkyl salicylates used include methyl salicylate, isobutyl salicylate, and 1-methyl trimethylene disalicylate. An example of one commercial material, Dycal, is given in Table 9.7, but its composition has been subjected to change over the years. 

Similarly, bases made from the metals of Group I on the periodic table, such as sodium hydroxide (NaOH) or potassium hydroxide (KOH), are called monobasic because they release one hydroxide ion into solution. Bases made up of Group II metals, such as calcium hydroxide [Ca(OH)2] or magnesium hydroxide [Mg(OH)2], release two hydroxide ions and are therefore dibasic. Like acids, any base that is capable of releasing more than one hydroxide ion into solution is called polybasic. 

This will give us the moles of calcium hydroxide instead of the grams, thus we need to add another step. We have moles and we need grams, the molar mass relates these two quantities. We determine the molar mass by using the formula and the atomic weights found in a table such as the periodic table. 

Experimental conditions. Table 1 lists the experimental conditions. Co shows the apparent initial concentration of reactants in the crystallizer. Series I, and 1 were conducted with stoichiometric feed ratio, with changing the feed ratio of reactants and with sodium chloride addition under the constant Co of magnesium chloride and calcium hydroxide, respectively. 

When the cranberry leaf extract was treated with calcium hydroxide followed by acidification and extraction with ether, parasorbic acid was indeed isolated. It was identified from the IR and HMR spectra of the crude extract and by identical retention time on two glc columns with an authentic sample of parasorbic acid. We then analyzed samples of the cranberry leaf extract by glc before and after treatment with calcium hydroxide (followed by acidification), samples of parasorbic acid alone, and extract plus parasorbic acid (in the presence of calcium hydroxide followed by acidification). Our results (Table I) show that parasorbic acid from the extract was obtained only upon calcium hydroxide treatment. This result agrees with Tschesche s observations on mountain ash berries. 

Table I. Parasorbic Acid Found After Calcium Hydroxide Treatment...

Now let s consider strong and weak bases. The common strong bases are easy to remember they are the alkali metal and alkaline earth metal hydroxides and oxides, such as calcium oxide (Table J.l). When the oxide dissolves in water, the oxide ions, O2-, accept protons to form hydroxide ions ... 

The Deionized Water-Alkaline System. The DI—Ca water analyses from the chemical feeder process are shown in Table I. As the amount of calcium ions in the deionized water was increased, the conductivity values became higher. The amounts of calcium in the Dl-Ca water can be measured by conductivity. The pH of the deionized water was 6.3. The pH of saturated calcium hydroxide solution is 12.3. Addition of 9.2 ppm Ca as Ca(OH)2 in the deionized water raised the pH to 9.9. The level of the pH increased with additional amounts of calcium ions in the DI water. The measurement and adjustment of the calcium solution flow was essential, both for washing and for the deacidification efficiency. 

Table 5.1 Solubility of calcium hydroxide (5 gCaO 1 ) (Bassett, B49)...

Table 9.9 Contents of calcium hydroxide and non-evaporable water in some pastes of Portland cement with and without microsilica (percentages on the ignited weight) (H53)... 

Table IV shows brightness retention of newsprint papers. Borohy-dride treatment increased initial brightness by as much as 10 brightness units. A decrease in brightness is generally observed when newsprint is subjected to a Ca(OH)2 wash. Treatment with either 0.1 or 1.0 NaBH4 followed by 0.002 calcium hydroxide washing also increased the brightness of newsprint. For the newsprint samples, the borohydride treatment did not produce a significantly greater improvement in brightness retention than the calcium hydroxide wash alone.

Table V. Effect of Calcium Hydroxide Wash Concentration on Aging of Foldur Kraft Paper ...

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