Final answer:
The milliequivalent (mEq) is not a measure of weight, but rather a measure of the chemical activity of an electrolyte, taking into consideration the concentration in millimoles and the charge on the ions.
Step-by-step explanation:
The statement that the milliequivalent is a measure of the weight of an electrolyte is false. In fact, the milliequivalent (mEq) is a measure of the chemical activity of an electrolyte based on the number of charges or ions it provides. For example, for ions with a single charge, one milliequivalent is equal to one millimole. However, for divalent ions like calcium, which has a charge of two, one milliequivalent equals 0.5 millimoles.
When expressing electrolyte concentrations, especially in clinical settings like blood plasma analysis, the milliequivalent takes into account both the ion concentration in millimoles and the valency. It provides a more clinically meaningful unit because it reflects the combining capacity of the electrolyte, which is crucial for understanding things like osmolality, electrolyte balance, and the osmotic pressure of body fluids.