milliequivalenter

A milliequivalent (mEq) is a unit of chemical equivalence. It represents one-thousandth of an equivalent. An equivalent is a measure of the reactive capacity of a substance, specifically its ability to react with or neutralize a specific amount of another substance. The concept of equivalents is used in chemistry to simplify calculations involving chemical reactions, particularly in stoichiometry and in the context of solutions.

The number of milliequivalents for a substance in a solution depends on its molar mass and its valence or charge. For ions, the charge is a key factor. For example, one mole of sodium ions (Na+) has one equivalent, while one mole of calcium ions (Ca2+) has two equivalents. This is because a calcium ion can react with twice as many anions as a sodium ion.

Milliequivalents are commonly used in medical and biological contexts, especially when discussing electrolytes in body fluids. For instance, electrolyte concentrations in blood, urine, and intravenous fluids are often expressed in milliequivalents per liter (mEq/L). This unit helps healthcare professionals understand the relative number of reactive ions present, which is crucial for assessing and treating imbalances. It provides a standardized way to compare the reactive potential of different ions, regardless of their differing molar masses.