- Feb 8, 2017
- Reaction score
- Menifee, CA
Thanks, that does make sense. Is that why Ca++ is listed, it has a ++ charge and requires -- to be equal?If you'll accept my attempt at an explanation: ppm is [commonly] mg/L (parts-per-million itself is a poor term because it's not at all about "parts"). Different ions have different masses. So, to take an example with easy numbers, if the mass of A is 1mg and the mass of B is 2mg, at 2ppm you'd have one of B but two of A in a liter.
The other issue is different electric charges. If the charge of C is +1 and the charge of D is -2, you'd need two of C to create a neutral charge against one of D.
Milliequivalents (mEq[/L]) takes both the mass difference and charge difference into account and tells you how many actual parts you have which can react with other parts, hence equivalents. In analogy, if you need 4 screws to connect 2 pieces of wood, and you have 8 screws and 4 pieces of wood (2 equivalents), you know you can complete 2 connections, and don't have to worry about what the masses of screws or pieces of wood are.
I don't know why the E is capitalized, but the m is lower-case because it stands for "milli", and if you wrote it as equivalents-sans-milli it would usually be 0.0..x.