Molarity: Difference between revisions
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'''Molarity''' (M) is a term used in [[chemistry]] to indicate the concentration of a [[solute]] in a [[solvent]], in units of M = [[mole (unit)|moles]]/[[liter]]. For a pure compound with virtually no solvent, molarities are in the range of about 10-18 M. Chemical solutions typically used in labs are often between 10 millimolar (mM) and 1 molar concentrations. Solutions of biological samples, containing proteins, enzymes or DNA, are more | '''Molarity''' (M) is a term used in [[chemistry]] to indicate the concentration of a [[solute]] in a [[solvent]], in units of M = [[mole (unit)|moles]]/[[liter]]. For a pure compound with virtually no solvent, molarities are in the range of about 10-18 M. Chemical solutions typically used in labs are often between 10 millimolar (mM) and 1 molar concentrations. Solutions of biological samples, containing proteins, enzymes or DNA, are more often used in the nanomolar (10<sup>-9</sup> M) or micromolar (10<sup>-6</sup> M) range, up to about 10 mM. For a solution containing many molecules, each molecule will have a molarity which is independent of the other components, unless they chemically react over time. Molarity is calculated by dividing the amount (mass) of the chemical being added into a solution by both its molecular mass (molecular weight MW) and the final volume of the solution. | ||
:<math> M = \frac{moles}{liter} = \frac{m}{MW | :<math> M = \frac{moles}{liter} = \frac{m}{MW \times V} </math> | ||
where | where | ||
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where ''n'' is an integer. | where ''n'' is an integer. | ||
For a monoprotic acid, 1M = 1N, while for diprotic and triprotic acids 1M = 2N and 1M = 3N, respectively. | For a monoprotic acid, 1M = 1N, while for diprotic and triprotic acids 1M = 2N and 1M = 3N, respectively.[[Category:Suggestion Bot Tag]] | ||
Latest revision as of 16:00, 20 September 2024
Molarity (M) is a term used in chemistry to indicate the concentration of a solute in a solvent, in units of M = moles/liter. For a pure compound with virtually no solvent, molarities are in the range of about 10-18 M. Chemical solutions typically used in labs are often between 10 millimolar (mM) and 1 molar concentrations. Solutions of biological samples, containing proteins, enzymes or DNA, are more often used in the nanomolar (10-9 M) or micromolar (10-6 M) range, up to about 10 mM. For a solution containing many molecules, each molecule will have a molarity which is independent of the other components, unless they chemically react over time. Molarity is calculated by dividing the amount (mass) of the chemical being added into a solution by both its molecular mass (molecular weight MW) and the final volume of the solution.
where
- m = mass of chemical added, in grams
- MW = molecular weight (mass), in grams/mole
- V = final volume of the solution
Relation to normality
A related concentration unit, normality (N), is often more convenient when one is dealing with acid-base reactions, because a 1 N solution of any acid will always neutralize a 1 N solution of any base. Normality is a multiple of molarity.
where n is an integer.
For a monoprotic acid, 1M = 1N, while for diprotic and triprotic acids 1M = 2N and 1M = 3N, respectively.