mM in chemistry stands for millimolar, which is a unit of concentration. It represents 1/1000 of a mole per liter (mol/L).
Here's a breakdown:
- Molar (M): Represents the concentration of a solution as moles of solute per liter of solution (mol/L).
- Millimole (mmol): Is 1/1000 of a mole. Just as a millimeter is 1/1000 of a meter.
- Millimolar (mM): Represents the concentration of a solution as millimoles of solute per liter of solution (mmol/L). This is equivalent to 10-3 mol/L.
Relationship between M and mM:
1 M = 1000 mM
Example:
A 5 mM solution of NaCl contains 0.005 moles of NaCl per liter of solution.
Why use mM?
Millimolar concentrations are frequently used in biochemistry, cell biology, and pharmacology because many biological molecules and drugs are effective at these lower concentration ranges. Working with mM values avoids the need to use very small decimal values that would be required if expressing concentrations in Molar (M).
Summary: mM is a convenient unit of concentration, especially when dealing with relatively low concentrations of substances in solution, commonly encountered in biological systems.
