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Concentration is a very common concept used in chemistry and related fields. It is the measure of how much of a given substance there 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.
To concentrate a solution, one must add more solute, or reduce the amount of solvent (for instance, by selective evaporation). By contrast, to dilute a solution, one must add more solvent, or reduce the amount of solute.
There exists a concentration at which no further solute will dissolve in a solution. At this point, the solution is said to be saturated. If additional solute is added to a saturated solution, it will not dissolve but form a suspension, colloid or emulsion. The point of saturation depends on many variables such as ambient temperature and the precise chemical nature of the solvent and solute.
Concentration may be expressed both qualitatively ('informally') or quantitatively ('numerically').
Qualitatively, solutions of relatively low concentration are described using adjectives such as "dilute," or "weak," while solutions of relatively high concentration are described as "concentrated," or "strong." As a rule, the more concentrated a chromatic solution is, the more intensely coloured it is.
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 listed below.
Note: Many units of concentration require measurement of a substance's volume, which is variable depending on ambient temperature and pressure. Unless otherwise stated, all the following measurements are assumed to be at standard state temperature and pressure (that is, 25 degrees CelsiusThe degree Celsius (°C) is a unit of temperature named after the Swedish astronomer Anders Celsius ( 1701 1744), who first proposed it in 1742. The Celsius temperature scale was designed so that the freezing point of water is 0 degrees, and the boiling po at 1 atmosphereWhen expressed as a measurement, an atmosphere is a unit of pressure based on the average atmospheric pressure at sea level on the earth. 1 atm : 101325 Pa 101325 kg/ m· s² 101325 N/ m² : 1013. 25 hPa 1013. 25 mbar : 101. 325 kPa : 1. 01325 bar : 760 torr).
Mass percentage denotes the massMass is a property of physical objects that, roughly speaking, measures the amount of matter they contain. It is a central concept of classical mechanics and related subjects. Strictly speaking, there are two different quantities called mass Inertial mass of a substance in a mixture as a percentage of the mass of the entire mixture. For instance: if a bottle contains 40 gramFor other meanings of gram see gram (disambiguation). The gram (also spelt gramme is a unit of measurement of mass, and is defined in the SI system of units as one thousandth of a kilogram. See 1 E -3 kg for comparisons with other masses. The symbol for gs of ethanol and 60 grams of waterDrinking water This article focuses on water as we experience it every day. The water (molecule) article describes water from a scientific and technical perspective. Water is an abundant substance on Earth. It exists in many forms, such as sea, rain, and, then it contains 40% ethanol by mass. Commercial concentrated aqueous reagents such as acid and bases are often labeled in concentrations of weight percentage with the specific gravity also listed. In older texts and references this is sometimes referred to as weight-weight percentage (abbreviated as w/w).