Concentration - wikipedia Concentration For other uses, see Concentration ( disambiguation ). In chemistry, concentration is the abundance of a constituent divided by the total volume of a mixture. Several types of mathematical description can be distinguished : mass concentration, molar concentration, number concentration, and volume concentration. The term concentration can be applied to any kind of chemical mixture, but most frequently it refers to solutes and solvents in solutions. The molar ( amount ) concentration has variants such as normal concentration and osmotic concentration. Contents 1 Qualitative description 2 Quantitative notation 2.1 Mass concentration 2.2 Molar concentration 2.3 Number concentration 2.4 Volume concentration 3 Related quantities 3.1 Normality 3.2 Molality 3.3 Mole fraction 3.4 Mole ratio 3.5 Mass fraction 3.6 Mass ratio 4 Dependence on volume 5 Table of concentrations and related quantities 6 See also 7 References Qualitative description These glasses containing red dye demonstrate qualitative changes in concentration. The solutions on the left are more dilute, compared to the more concentrated solutions on the right. Often in informal, non-technical language, concentration is described in a qualitative way, through the use of adjectives such as `` dilute '' for solutions of relatively low concentration and `` concentrated '' for solutions of relatively high concentration. To concentrate a solution, one must add more solute ( for example, alcohol ), or reduce the amount of solvent ( for example, water ). By contrast, to dilute a solution, one must add more solvent, or reduce the amount of solute. Unless two substances are fully miscible 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, except in certain circumstances, when supersaturation may occur. Instead, phase separation will occur, leading to coexisting phases, either completely separated or mixed as a suspension. The point of saturation depends on many variables such as ambient temperature and the precise chemical nature of the solvent and solute. Concentrations are often called levels, reflecting the mental schema of levels on the vertical axis of a graph, which can be high or low ( for example, `` high serum levels of bilirubin '' are concentrations of bilirubin in the blood serum that are greater than normal ). Quantitative notation There are four quantities that describe concentration : Mass concentration Main article : Mass concentration ( chemistry ) The mass concentration ρ i ( displaystyle \rho _ ( i ) ) is defined as the mass of a constituent m i ( displaystyle m_ ( i ) ) divided by the volume of the mixture V ( displaystyle V ) : ρ i = m i V. ( displaystyle \rho _ ( i ) = ( \frac ( m_ ( i ) ) ( V ) ). ) The SI unit is kg / m ( equal to g / L ). Molar concentration Main article : Molar concentration The molar concentration c i ( displaystyle c_ ( i ) ) is defined as the amount of a constituent n i ( displaystyle n_ ( i ) ) ( in moles ) divided by the volume of the mixture V ( displaystyle V ) : c i = n i V. ( displaystyle c_ ( i ) = ( \frac ( n_ ( i ) ) ( V ) ). ) The SI unit is mol / m. However, more commonly the unit mol / L ( = mol / dm ) is used. Number concentration Main article : Number concentration The number concentration C i ( displaystyle C_ ( i ) ) is defined as the number of entities of a constituent N i ( displaystyle N_ ( i ) ) in a mixture divided by the volume of the mixture V ( displaystyle V ) : C i = N i V. ( displaystyle C_ ( i ) = ( \frac ( N_ ( i ) ) ( V ) ). ) The SI unit is 1 / m. Volume concentration The volume concentration φ i ( displaystyle phi _ ( i ) ) ( do not confuse with volume fraction ) is defined as the volume of a constituent V i ( displaystyle V_ ( i ) ) divided by the volume of the mixture V ( displaystyle V ) : φ i = V i V. ( displaystyle phi _ ( i ) = ( \frac ( V_ ( i ) ) ( V ) ). ) Being dimensionless, it is expressed as a number, e.g., 0.18 or 18 % ; its unit is 1. Related quantities Several other quantities can be used to describe the composition of a mixture. Note that these should not be called concentrations. Normality Main article : Normality ( chemistry ) Normality is defined as the molar concentration c i ( displaystyle c_ ( i ) ) divided by an equivalence factor f e q ( displaystyle f_ ( mathrm ( eq ) ) ). Since the definition of the equivalence factor depends on context ( which reaction is being studied ), IUPAC and NIST discourage the use of normality. Molality Main article : Molality ( Not to be confused with Molarity ) The molality of a solution b i ( displaystyle b_ ( i ) ) is defined as the amount of a constituent n i ( displaystyle n_ ( i ) ) ( in moles ) divided by the mass of the solvent m s o l v e n t ( displaystyle m_ ( mathrm ( solvent ) ) ) ( not the mass of the solution ) : b i = n i m s o l v e n t. ( displaystyle b_ ( i ) = ( \frac ( n_ ( i ) ) ( m_ ( mathrm ( solvent ) ) ) ). ) The SI unit for molality is mol / kg. Mole fraction Main article : Mole fraction The mole fraction x i ( displaystyle x_ ( i ) ) is defined as the amount of a constituent n i ( displaystyle n_ ( i ) ) ( in moles ) divided by the total amount of all constituents in a mixture n t o t ( displaystyle n_ ( mathrm ( tot ) ) ) : x i = n i n t o t. ( displaystyle x_ ( i ) = ( \frac ( n_ ( i ) ) ( n_ ( mathrm ( tot ) ) ) ). ) The SI unit is mol / mol. However, the deprecated parts - per notation is often used to describe small mole fractions. Mole ratio Main article : Mixing ratio The mole ratio r i ( displaystyle r_ ( i ) ) is defined as the amount of a constituent n i ( displaystyle n_ ( i ) ) divided by the total amount of all other constituents in a mixture : r i = n i n t o t − n i. ( displaystyle r_ ( i ) = ( \frac ( n_ ( i ) ) ( n_ ( mathrm ( tot ) ) - n_ ( i ) ) ). ) If n i ( displaystyle n_ ( i ) ) is much smaller than n t o t ( displaystyle n_ ( mathrm ( tot ) ) ), the mole ratio is almost identical to the mole fraction. The SI unit is mol / mol. However, the deprecated parts - per notation is often used to describe small mole ratios. Mass fraction Main article : Mass fraction ( chemistry ) The mass fraction w i ( displaystyle w_ ( i ) ) is the fraction of one substance with mass m i ( displaystyle m_ ( i ) ) to the mass of the total mixture m t o t ( displaystyle m_ ( mathrm ( tot ) ) ), defined as : w i = m i m t o t. ( displaystyle w_ ( i ) = ( \frac ( m_ ( i ) ) ( m_ ( mathrm ( tot ) ) ) ). ) The SI unit is kg / kg. However, the deprecated parts - per notation is often used to describe small mass fractions. Mass ratio Main article : Mixing ratio The mass ratio ζ i ( displaystyle zeta _ ( i ) ) is defined as the mass of a constituent m i ( displaystyle m_ ( i ) ) divided by the total mass of all other constituents in a mixture : ζ i = m i m t o t − m i. ( displaystyle zeta _ ( i ) = ( \frac ( m_ ( i ) ) ( m_ ( mathrm ( tot ) ) - m_ ( i ) ) ). ) If m i ( displaystyle m_ ( i ) ) is much smaller than m t o t ( displaystyle m_ ( mathrm ( tot ) ) ), the mass ratio is almost identical to the mass fraction. The SI unit is kg / kg. However, the deprecated parts - per notation is often used to describe small mass ratios. Dependence on volume Concentration depends on the variation of the volume of the solution due mainly to thermal expansion. Table of concentrations and related quantities Concentration type Symbol Definition SI unit other unit ( s ) mass concentration ρ i ( displaystyle \rho _ ( i ) ) or γ i ( displaystyle gamma _ ( i ) ) m i / V ( displaystyle m_ ( i ) / V ) kg / m g / 100mL ( = g / dL ) molar concentration c i ( displaystyle c_ ( i ) ) n i / V ( displaystyle n_ ( i ) / V ) mol / m M ( = mol / L ) number concentration C i ( displaystyle C_ ( i ) ) N i / V ( displaystyle N_ ( i ) / V ) 1 / m 1 / cm volume concentration φ i ( displaystyle phi _ ( i ) ) V i / V ( displaystyle V_ ( i ) / V ) m / m Related quantities Symbol Definition SI unit other unit ( s ) normality c i / f e q ( displaystyle c_ ( i ) / f_ ( mathrm ( eq ) ) ) mol / m N ( = mol / L ) molality b i ( displaystyle b_ ( i ) ) n i / m s o l v e n t ( displaystyle n_ ( i ) / m_ ( mathrm ( solvent ) ) ) mol / kg mole fraction x i ( displaystyle x_ ( i ) ) n i / n t o t ( displaystyle n_ ( i ) / n_ ( mathrm ( tot ) ) ) mol / mol ppm, ppb, ppt mole ratio r i ( displaystyle r_ ( i ) ) n i / ( n t o t − n i ) ( displaystyle n_ ( i ) / ( n_ ( mathrm ( tot ) ) - n_ ( i ) ) ) mol / mol ppm, ppb, ppt mass fraction w i ( displaystyle w_ ( i ) ) m i / m t o t ( displaystyle m_ ( i ) / m_ ( mathrm ( tot ) ) ) kg / kg ppm, ppb, ppt mass ratio ζ i ( displaystyle zeta _ ( i ) ) m i / ( m t o t − m i ) ( displaystyle m_ ( i ) / ( m_ ( mathrm ( tot ) ) - m_ ( i ) ) ) kg / kg ppm, ppb, ppt See also Dilution ratio Dose concentration Serial dilution Wine / water mixing problem References ^ Jump up to : IUPAC, Compendium of Chemical Terminology, 2nd ed. ( the `` Gold Book '' ) ( 1997 ). Online corrected version : ( 2006 -- ) `` concentration ''. Jump up ^ IUPAC, Compendium of Chemical Terminology, 2nd ed. ( the `` Gold Book '' ) ( 1997 ). Online corrected version : ( 2006 -- ) `` volume fraction ''. Articles related to solutions Solution Ideal solution Aqueous solution Solid solution Buffer solution Flory -- Huggins Mixture Suspension Colloid Phase diagram Eutectic point Alloy Saturation Supersaturation Serial dilution Dilution ( equation ) Apparent molar property Miscibility gap Concentration and related quantities Molar concentration Mass concentration Number concentration Volume concentration Normality Percentage solution Molality Mole fraction Mass fraction Isotopic abundance Mixing ratio Solubility Solubility equilibrium Total dissolved solids Solvation Solvation shell Enthalpy of solution Lattice energy Raoult 's law Henry 's law Solubility table ( data ) Solubility chart Solvent ( Category ) Acid dissociation constant Protic solvent Inorganic nonaqueous solvent Solvation List of boiling and freezing information of solvents Partition coefficient Polarity Hydrophobe Hydrophile Lipophilic Amphiphile Lyonium ion Retrieved from `` https://en.wikipedia.org/w/index.php?title=Concentration&oldid=801689246 '' Categories : Analytical chemistry Chemical properties Talk Contents About Wikipedia Afrikaans Bân - lâm - gú Български Català Čeština ChiShona Dansk Deutsch Eesti Ελληνικά Español Esperanto Euskara فارسی Français Gaeilge ગુજરાતી 한국어 हिन्दी Hrvatski Ido Bahasa Indonesia IsiXhosa Italiano עברית Kreyòl ayisyen Latviešu Magyar Македонски മലയാളം Nederlands 日本 語 Norsk Norsk nynorsk Polski Português Română Русский Simple English Slovenčina Slovenščina کوردی Српски / srpski Srpskohrvatski / српскохрватски Suomi Svenska தமிழ் తెలుగు ไทย Türkçe Українська Tiếng Việt 粵語 中文 Edit links This page was last edited on 21 September 2017, at 06 : 21. 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Question: what is the meaning of concentration in science
Answer: the abundance of a constituent divided by the total volume of a mixture