Calcium sulfate molarity

Tacztrk et al. (1992) studied sulfoaluminate-modifred cements with C4A3S contents between 5% and 20% and with a sulfoaluminate/calcium sulfate molar ratio of 1 8. Calcium sulfate was added in the form of arrhydrite or gypsum. The form of calcium... 

The decrease in molar volume during calcination of CaC03 to CaO has the effect of increasing the porosity of the sorbent which is important to the efficient utilization of limestone. The gas-solid reaction between S02 and limestone sorbent consists of a number of steps (2.) diffusion of gaseous S02 through the pores of the calcined limestone, reaction of 02 with CaO to form calcium sulfate (CaSO,), and diffusion of S02 through the calcium sulfate product layer to react with additional CaO in the particle. Unfortunately, the sulfation reaction ... 

Step 3 Determine the molar mass of calcium sulfate. Use the molar mass to find the mass in grams, using the formula below ... 

The surfactant AOT ( purum grade, Fluka) was purified as described by Kotlarchyk 22). The AOT solution was filtered through a 0.2-)im Millipore filter prior to drying in vacuo for eight hours. The AOT was stored in a desiccator over anhydrous calcium sulfate. The molar water-to-AOT ratio (W) was assumed to be 1 in the purified, dried solid (2J ). Water was distilled and filtered through a Millipore Milli-Q system. Ethane, propane ("CP" grade, Linde), and xenon (Research grade, Linde) were used as received. The alkanes had a reported purity of >99% (Aldrich) and were used as received. 

Ramachandran and Smith obtained satisfactory agreement with experimental results on the reduction of nickel oxide with carbon monoxide (pore opening case) by considering the product layer diffusion coefficient as an adjustable parameter. Similarly, the model predicted pore closure and reaction die-off for the reaction of calcium oxide with sulfur dioxide, where the molar volume of calcium sulfate product is about three times that of the calcium oxide reactant. 

KEY WORDS plaster, gypsum, anhydrite, vapor pressure, humidity, measure and integration. hydration ratio, plaster rocks, calcium sulfate P-hemihydraie. calcium sulfate dihydrate, reactor, water vapor molar fraction, isothermal calorimeter, thermoelectric captor... 

Procedure Mix several pinches of calcium sulfate with water leave the mixture to stand overnight the solution becomes clear, a big solid residue can be observed at the bottom. Dip the conductivity tester into distilled water, then into the saturated solution. Prepare a 0.1 molar magnesium sulfate solution and dilute it with the help of the graduated cylinder once at 1 2 and once at 1 10. Measure the conductivity of these solutions and compare with the conductivity of saturated calcium sulfate solution. 

Observation Saturated calcium sulfate solution shows a good electrical conductivity. The saturated solution and the 0.01 molar solution of magnesium sulfate produce similar reading on the conductivity tester. This concentration can therefore be used for the calculation of the solubility product of calcium sulfate. 

The two chlorides have almost identical solubilities, except that the NaCl solution has a molar concentration of ions of 2 x 5.4 = 10.8 mol dm and that of the CaCl2 solution is 3 x 5.0 = 15.0 mol dm . Sodium carbonate solution (molar ion concentration = 6.03 mol dm ) is less concentrated than that of sodium chloride (molar ion concentration = 10.8 mol dm ). When both cations and anions are doubly charged, as in CaC03, the relatively high lattice enthalpy predominates to make the compound insoluble. Calcium sulfate is only sparingly soluble, but sodium sulfate is soluble. The double charge on the calcium ion favours a larger lattice enthalpy compared to the enthalpy of hydration. 

An important gas-solid reaction for wHich porosity decreases with time of exposure to the reactant gas is the absorption of SO2 by calcined limestone (CaO) or dolomite (CaO/MgO) to produce calcium sulfate (CaSO or CaSO./MgO), which has a larger molar volume than the reactant solid. If diffusional limitations in the pores are important, the porosity decrease will be greater near the surface of the solid particle and pores will plug, limiting access to part of the reactant solid. 

The hydration of mixtures of CuA7 CaF2, C3S, and CaS04 with various additives has been investigated.The molar ratio of Cj iA7 CaF2 to C3S was 1.0 to 15.4. The SO3/AI2O3 molar ratio was 1.0. Hydration occurred at 20°C with a water/solid ratio = 0.60. The additives included calcium sulfate hemihydrate, sodium sulfate, sodium carbonate, and citric... 

Under certain conditions of pressures and temperature, the formed sohd B can present a distance to stoichiometry with respect to gas or dissolve gas significantly. We assume that only one gas is produced with molar mass Mq. Take s as the amount of gas that remains fixed per mole of B. We will quote as an example the dehydration of calcium sulfate dihydrate (gypsum) into plaster, which is, in fact, a sohd solution of water in calcium sulfate whose composition varies practically from 0 to 0.66 and which takes value of 0.5 under normal conditions of temperature and moisture from where the name of semi-hydrate comes, which is sometimes given to this solid solution. 

It was observed that the most efficient oxidant was KMnO absorbed on a fourfold molar amount of CUSO4.5H2O (100% yield), but attempts were made to oxidize 2-heptanol, under solvent-free conditions, by KMnO alone (i.e., in the absence of the support of an inorganic salt hydrate) were absolutely unsuccessful. Various inorganic salts were tried and yielded varied amounts of the product. The better supports include nickel sulfate (90%), zinc sulfate (74%), and cobalt sulfate (41%) while other supports were not that interesting like magnesium sulfate (12%), calcium sulfate (11%) and barium chloride (3%). Zeolite HZSM-5 was used as a catalyst for the oxidation of alcohols to the corresponding carbonyl compound with chromium trioxide under solvent-free conditions and microwave irradiation (Heravi et al., 1999). 

Numerous methods for the synthesis of salicyl alcohol exist. These involve the reduction of salicylaldehyde or of salicylic acid and its derivatives. The alcohol can be prepared in almost theoretical yield by the reduction of salicylaldehyde with sodium amalgam, sodium borohydride, or lithium aluminum hydride by catalytic hydrogenation over platinum black or Raney nickel or by hydrogenation over platinum and ferrous chloride in alcohol. The electrolytic reduction of salicylaldehyde in sodium bicarbonate solution at a mercury cathode with carbon dioxide passed into the mixture also yields saligenin. It is formed by the electrolytic reduction at lead electrodes of salicylic acids in aqueous alcoholic solution or sodium salicylate in the presence of boric acid and sodium sulfate. Salicylamide in aqueous alcohol solution acidified with acetic acid is reduced to salicyl alcohol by sodium amalgam in 63% yield. Salicyl alcohol forms along with -hydroxybenzyl alcohol by the action of formaldehyde on phenol in the presence of sodium hydroxide or calcium oxide. High yields of salicyl alcohol from phenol and formaldehyde in the presence of a molar equivalent of ether additives have been reported (60). Phenyl metaborate prepared from phenol and boric acid yields salicyl alcohol after treatment with formaldehyde and hydrolysis (61). 

The original product sold in the United States contains -30% lithium hypochlorite (35% available chlorine), 34% sodium chloride, 20% of potassium and sodium sulfates, 3% lithium chloride, 3% lithium chlorate, 2% lithium hydroxide, 1% lithium carbonate, and the balance is water. It is made from lithium sulfate that is extracted into water from a lithium aluminum silicate ore after it is treated with sulfuric acid. The resulting solution also contains sodium and potassium sulfates. It is neutralized with calcium carbonate to pH 6, treated to remove calcium and magnesium, filtered, and concentrated. Sodium hydroxide is added to convert lithium carbonate to lithium hydroxide. The solution is cooled to 0°C and the resulting sodium carbonate decahydrate crystals are removed by filtration. Slightly more sodium hydroxide than the molar equivalent of lithium hydroxide is then... 

Note that the molar enthalpies of melting of the salt hydrates are generally rather larger than those of similar anhydrous salts melting at a much higher temperature. Compare, for instance the Am///kJ moF of lithium salt trihydrates with the anhydrous salts nitrate 36.4 vs. 26.7 and perchlorate 40.6 vs. 17.0, the sodium salt decahydrates with the anhydrous salts carbonate 72.0 vs. 30.0, sulfate 78.7 vs. 23.0, and the calcium salt hexahydrates with the anhydrous salts chloride 37.2 vs. 28.5, bromide 35.6 vs. 28.9. 

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