Why is alkalinity reported as “mg/L as CaCO3”? Units of mg/L are a “mass dissolved in a liquid.” Reporting alkalinity as “mg/L as CaCO3” specifies that the sample has an alkalinity equal to that of a solution with a certain amount of calcium carbonate (CaCO3) dissolved in water .
Why is alkalinity measured in CaCO3?
Note: We have reacted the alkalinity species (CaCO3) with the hydrogen ion, since it is the property of alkalinity to react with an acid . ... Therefore, a mass equivalent of alkalinity is equal to 50 mass units expressed as CaCO3.
What is the total alkalinity in mg L as CaCO3?
Total alkalinity is expressed as milligrams per liter (mg/L) or parts per million (ppm) of calcium carbonate (CaCO3). In the aquarium industry, total alkalinity may be referred to as “carbonate hardness” or “KH,” which is often measured in degrees (dKH) rather mg/L or ppm. One dKH is equal to 17.9 mg/L or 17.9 ppm.
How do you express alkalinity as CaCO3?
Multiply alkalinity in “Eq/L” by the equivalent weight of CaCO3 to calculate it in g/L. In our example, Alkalinity as CaCO3 = 0.0097 Eq/L x 50 g/Eq = 0.485 g/L = 485 mg/L. Thus, if the solution density is close or equal to 1, then ppm = mg/L.
What is mg L as CaCO3?
Multiplty the mg/l of the substances listed below by the corresponding factors to obtain mg/l as CaCO3. For example, 70 mg/l of Mg + + would be (70) (4 10) = 287 mg/l as CaCO3.
What is the normal range of alkalinity?
Levels of 20-200 mg/L are typical of fresh water. A total alkalinity level of 100-200 mg/L will stabilize the pH level in a stream. Levels below 10 mg/L indicate that the system is poorly buffered, and is very susceptible to changes in pH from natural and human-caused sources.
What is the difference between alkalinity and total alkalinity?
Alkalinity is expressed as phenolphthalein alkalinity or total alkalinity. Phenolphthalein alkalinity measures the hydroxides and half the carbonates at a pH 8.3. Total alkalinity measures all carbonate, bicarbonate, and hydroxide alkalinity at a pH 4.5 (approximately).
How do you explain alkalinity?
Alkalinity is a chemical measurement of a water’s ability to neutralize acids . Alkalinity is also a measure of a water’s buffering capacity or its ability to resist changes in pH upon the addition of acids or bases.
How do you calculate alkalinity?
- Step 1: Convert g/m3 to eq/m3. In this step, divide the raw concentrations of bicarbonate, carbonate, and hydroxide by their EW values, which is derived from their molecular masses. ...
- Step 2: Find [H+] ...
- Step 3: Multiply [H+] by 1,000. ...
- Step 4: Solve for Alkalinity.
How do you calculate total alkalinity?
Alkalinity is oftentimes measured in seawater and drinking water, and can be calculated as the sum of ion concentrations [HCO3-]+2x[CO3(-2)]+[OH-]-[H+]. To complete this calculation, you will need to perform a titration on your sample , from which you can derive the alkalinity of your sample.
What are the different types of alkalinity?
Depending upon the pH of the water, alkalinity can exist in water in three basic forms: carbonate (CO 3 ), bicarbonate (HCO 3 ), or hydroxide (OH) . Total alkalinity is the sum of these three forms.
Why is hardness expressed in terms of CaCO3 equivalent?
Hardness is perhaps similar. CaCO3 is used as a unit so calculations can be easily made on the level and severity of hardness effects , whether the hardness is calcium hardness, magnesium hardness, carbonate hardness or non-carbonate hardness. ... So the expression as CaCO3 is to make it easy reference.
What is meant by phenolphthalein alkalinity?
Phenolphthalein alkalinity is a specific category of alkalinity. It is determined by titrating to pH 8.3 (where phenolphthalein changes colour). If you are titrating OH- with a strong acid, the titration curve looks like this. ... Thus, phenolphthalein alkalinity gives the total hydroxide and half the carbonate level .
What is the equivalent of CaCO3?
For example, the equivalent weight of calcium is 20.04, as we calculated previously. One equivalent of calcium would therefore be 20.04 grams of calcium. The equivalent weight of calcium carbonate (CaCO 3 ) is 50.045 , as calculated above. One equivalent of CaCO 3 is therefore 50.045 grams of CaCO 3 .
What do you mean by CaCO3 equivalent?
An expression of the concentration of specified constituents in water in terms of their equivalent value to calcium carbonate . For example, the hardness in water that is caused by calcium, magnesium, and other ions is usually described as calcium carbonate equivalent.
How do you convert MEQ L to mg L?
Calcium has a molecular weight of 40.08 grams/mole Calcium has a valence of +2 The equivalent weight = (40.08grams/mole)/(2 equivalents/mole) = 20.04 grams/eq To convert to mg/meq you simply multiply g/eq by 1000 mg/g and divide by 1000 meq/eq , thus g/eq = mg/meq If your sample contains 30 mg Ca/L, what is the ...
