Substance concentration

Substance concentration, also molar concentration or molarity is equal to the ratio of the substance amount of the substance contained in the system to the volume of this system:
 * $$ c = \frac{n}{V}$$


 * where
 * c is the substance concentration,
 * n is the quantity of substance in the system,
 * V is the volume of the system.

It is most often used for solutions, so it expresses the concentration of a substance in solution in moles per liter of solvent. The most commonly used unit is mol/l and its fractions (mmol/l, μmol/l, nmol/l).

It is important to distinguish molarity from molality. For strongly diluted aqueous solutions, the value of molarity and molality hardly differ, because 1 liter of water is approximately equal to 1 kg of water and the amount of dissolved substances can be neglected. For more concentrated solutions, where the volume of solutes contributes significantly to the total volume of the solution, the molarity of the solution is greater than its molality.

Resources

 * ws:Látková koncentrace