Calcium carbonate equivalent

Calcium carbonate is used to buffer acidic soils. In soils that contain sulfuric acid calcium carbonate, it will react with the acid to produce calcium sulfate (CaS04), carbon dioxide, and water H SO., + CaCO.M —> CaSO., + CCU + H.O... The ability ofvari-ous limes to neutralize acid in a soil is given in terms of calcium carbonate equivalents. In this system, limestone has a calcium carbonate equivalent of 100. If a slaked lime (calcium hydroxide) has a calcium carbonate equivalent of 150, then only two-thirds as much of slaked lime would be needed to achieve the same neutralizing effect. Calcium carbonate... 

Numerous tertiary amines that also contain carboxylic acid groups form remarkably stable chelates with many metal ions. Ethylenediamine tetra-acetic acid (EDTA) can be used for determination of 40 elements by direct titration using metal-ion indicators for endpoint detection. Direct titration procedures are limited to metal ions that react rapidly with EDTA. Back titration procedures are useful for the analysis of cations that form very stable EDTA complexes and for which a satisfactory indicator is not available. EDTA is also used for determining water hardness the total concentration of calcium and magnesium expressed in terms of the calcium carbonate equivalent. 

Calcium carbonate equivalents The impurities of naturally occurring waters are frequently expressed as CaCOs equivalents (Table 6.9). To convert the ppm (mg/1) of a given constiment to ppm expressed as CaCOs, multiply ppm by the ratio of the molecular weight (MW) of CaCOs to that of the constituent. For example, to convert ppm of carbonate to ppm of CaCOs equivalents midtiply by 1.67. The MW of CaCOs is 100. 

Table 6.9 Calcium carbonate equivalent of common substances...

Rendzinas (E) Other soils having a mollic A horizon which contains or immediately overlies calcareous material with a calcium carbonate equivalent of more than 40% (when the A horizon contains a high amount of finely divided calcium carbonate the color requirements of the mollic A horizon may be waived) ... 

Figure 1. Hardness of tap water from UDM chemistry building in February 2007 measured as calcium carbonate equivalents. The concentrations shown are averaged values of data points within 2 ppm.

Hardness is the calcium carbonate equivalent of caldum and magnesium salts. 

I. Parts per million (ppm) is the. most commonly used unit of hardness and represents the number of parts of calcium carbonate, equivalent to hardness causing ions present, per million parts of water. 

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). 

Hardness as calcium carbonate The expression ascribed to the value obtained when the hardness-forming salts are calculated in terms of equivalent quantities of calcium carbonate a convenient method of reducing all salts to a common basic for comparison. 

Acidity The capacity of water or wastewater to neutralize bases. Acidity is expressed in milligrams per liter of equivalent calcium carbonate. Acidity is not the same as Ph. 

Selective hydroxylation with osmium tetroxide (one equivalent in ether-pyridine at 0 ) converts (27) to a solid mixture of stereoisomeric diols (28a) which can be converted to the corresponding secondary monotoluene-sulfonate (28b) by treatment with /7-toluenesulfonyl chloride in methylene dichloride-pyridine and then by pinacol rearrangement in tetrahydrofuran-lithium perchlorate -calcium carbonate into the unconjugated cyclohepte-none (29) in 41-48 % over-all yield from (27). Mild acid-catalyzed hydrolysis of the ketal-ketone (29) removes the ketal more drastic conditions by heating at 100° in 2 hydrochloric acid for 24 hr gives the conjugated diketone (30). 

Base catalyzed pinacol rearrangement of vicinal m-glycol monotosylates is a simple and useful general method for preparing perhydroazulenes. Thus, treatment of cholestane-5a,6a-diol 6-tosylate (115a) with either one mole-equivalent of potassium t-butoxide in f-butanol at 25° or with calcium carbonate in dimethylformamide at 100° gives a quantitative yield of 10(5 6/5H)... 

A simple and direct approach to 10(5 4j H)<2Z)eo-5-lceto derivatives lacking functionality in ring A is the controlled pinacol rearrangement of vicinal cw-diols analogous to the process described in the previous section. An example is the reaction of cholestane-4a,5a-diol 4-tosylate (136) with 1 mole-equivalent of potassium t-butoxide or with dimethylforraamide-calcium carbonate at reflux which gives a quantitative yield of Q(5ApH)abeo-cholestan-5-one (137). ... 

Finishing of the filler surfaces may also greatly affect the system viscosity. For mica-filled PP [31] and various thermoplastics filled with calcium carbonate [202, 261] it was shown that the relative viscosity of filled systems was lower than that of systems which contained equivalent quantitied of unfinished filler. Note that in contrast to viscosity in shear, the viscosity in stretching is higher for systems with treated filler [202]. 

Equivalent weight or gram equivalent, a mole divided by the valency of the substance. Example a mole of sodium chloride — 58.45 g, valency = 1, therefore equiv. wt = 58.45. A mole of calcium carbonate = 100.08 g, valency = 2, therefore equiv. wt. = 50.04. 

White and brown flour in the UK have to be fortified with calcium, iron, thiamine (vitamin Bl), and niacin (vitamin B3 also known as nicotinic acid) as follows flour should contain not less than 235 mg per 100 g and not more than 390 mg per 100 g calcium carbonate, iron not less than 1.65 mg, thiamine (vitamin Bl) not less than 0.24 mg, and nicotinic acid not less than 1.6 mg or nicotinamide (which is nutritionally equivalent to nicotinic acid) not less than 1.60 mg. 

Finally, it is intriguing that in terms of biomineralization, invertebrates have based their reliance on calcium carbonates, while vertebrates appear to have used almost exclusively calcium phosphate. We say almost, because, while the use of calcium phosphates for biomineralization is an invention of some vertebrates, they still use calcium carbonate for the formation of otoliths4 of the inner ear. It remains to be established if the equivalent of the gene starmaker required for otolith formation in zebrafish has homologues among invertebrates. 

English degree chem A unit of water hardness, equal to 1 part calcium carbonate to 70,000 parts water equivalent to 1 grain of calcium carbonate per gallon of water. Also known as Clark degree, ir -glish di.gre ... 

The most significant dissolved ionic solid in most natural freshwater is calcium carbonate (actually present mainly as the bicarbonate), and so, for the purpose of water treatment, it is convenient to express the concentration of any ionic solute as a CaCOs equivalent. The formula weight of the solute is divided by the valence and by the number of its cations—for CaCOs itself, this comes to 50.0—and the concentration (usually in mg kg-1, ppm) is converted to an equivalent concentration of CaC03 on this basis.2... 

The weight of calcium carbonate added is equivalent to 0.1-0.5% that of the nitrocellulose. 

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