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Normality is defined as the number of gram or mole equivalents of solute present in one liter of solution.The SI unit of normality is equivalents per liter (Eq/L). = where N is normality, m sol is the mass of solute in grams, EW sol is the equivalent weight of solute, and V soln is the volume of the entire solution in liters.
Environmental laboratories typically report concentrations for anion and cation parameters using units of mass/volume, usually mg/L. In order to convert the mass concentration to an equivalent concentration the following mathematical relationship is used: (mass concentration) * (ionic charge) / (molecular weight) = (equivalent concentration)
Very often, the measure is used in terms of milliequivalents of solute per litre of solution (or milliNormal, where meq/L = mN). This is especially common for measurement of compounds in biological fluids; for instance, the healthy level of potassium in the blood of a human is defined between 3.5 and 5.0 mEq/L.
Alkalinity is typically reported as mg/L as CaCO 3. (The conjunction "as" is appropriate in this case because the alkalinity results from a mixture of ions but is reported "as if" all of this is due to CaCO 3.) This can be converted into milliequivalents per Liter (meq/L) by dividing by 50 (the approximate MW of CaCO 3 divided by 2).
Since one degree KH = 17.848 mg/L CaCO 3, this solution has a KH of 4.0052 degrees. Carbonate hardness should not be confused with a similar measure Carbonate Alkalinity which is expressed in either [milli[equivalent]s] per litre (meq/L) or ppm. Carbonate hardness expressed in ppm does not necessarily equal carbonate alkalinity expressed in ppm.
RSC is expressed in meq/L units. RSC should not be higher than 1 and preferably less than +0.5 for considering the water use for irrigation. [5] The formula for calculating RSC index is: RSC index = [HCO 3 + CO 3] − [Ca + Mg] RSC index = HCO 3 /61 + CO 3 /30 – Ca/20 – Mg/12 (in case the ionic concentrations are measured in mg/L or ppm as ...
The molar ionic strength, I, of a solution is a function of the concentration of all ions present in that solution. [3]= = where one half is because we are including both cations and anions, c i is the molar concentration of ion i (M, mol/L), z i is the charge number of that ion, and the sum is taken over all ions in the solution.
It is commonly expressed in mass of oxygen consumed over volume of solution, which in SI units is milligrams per liter (mg/L). A COD test can be used to quickly quantify the amount of organics in water. The most common application of COD is in quantifying the amount of oxidizable pollutants found in surface water (e.g. lakes and rivers) or ...