Concentration is a very common concept used in chemistry and related fields. It is the measure of how much of a given substance is mixed with another substance. This can apply to any sort of chemical mixture, but most frequently is used in relation to solutions, where it refers to the amount of solute dissolved in a solvent.

Qualitatively, solutions of relatively low concentration are described as “dilute,” or “weak,” while solutions of relatively high concentration are described as “concentrated,” or “strong.”

Quantitative notation of concentration is far more informative and useful from a scientific point of view. There are a number of different ways to quantitatively express concentration; the most common are discussed in this course.

The choice of a particular concentration term depends on many factors like convenience, experimental limitations etc.