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  2. Parts-per notation - Wikipedia

    en.wikipedia.org/wiki/Parts-per_notation

    In fractions like "2 nanometers per meter" (2 n m / m = 2 nano = 2×10 −9 = 2 ppb = 2 × 0.000 000 001), so the quotients are pure-number coefficients with positive values less than or equal to 1. When parts-per notations, including the percent symbol (%), are used in regular prose (as opposed to mathematical expressions), they are still pure ...

  3. Mass fraction (chemistry) - Wikipedia

    en.wikipedia.org/wiki/Mass_fraction_(chemistry)

    Mass fraction can also be expressed, with a denominator of 100, as percentage by mass (in commercial contexts often called percentage by weight, abbreviated wt.% or % w/w; see mass versus weight). It is one way of expressing the composition of a mixture in a dimensionless size ; mole fraction (percentage by moles , mol%) and volume fraction ...

  4. Decibel - Wikipedia

    en.wikipedia.org/wiki/Decibel

    Therefore, the bel represents the logarithm of a ratio between two power quantities of 10:1, or the logarithm of a ratio between two root-power quantities of √ 10:1. [16] Two signals whose levels differ by one decibel have a power ratio of 10 1/10, which is approximately 1.258 93, and an amplitude (root-power quantity) ratio of 10 1/20 (1.122 ...

  5. Percentage - Wikipedia

    en.wikipedia.org/wiki/Percentage

    In mathematics, a percentage (from Latin per centum 'by a hundred') is a number or ratio expressed as a fraction of 100. It is often denoted using the percent sign (%), [ 1] although the abbreviations pct., pct, and sometimes pc are also used. [ 2] A percentage is a dimensionless number (pure number), primarily used for expressing proportions ...

  6. Volume fraction - Wikipedia

    en.wikipedia.org/wiki/Volume_fraction

    In chemistry and fluid mechanics, the volume fraction is defined as the volume of a constituent Vi divided by the volume of all constituents of the mixture V prior to mixing: [ 1] Being dimensionless, its unit is 1; it is expressed as a number, e.g., 0.18. It is the same concept as volume percent (vol%) except that the latter is expressed with ...

  7. Molality - Wikipedia

    en.wikipedia.org/wiki/Molality

    In chemistry, molality is a measure of the amount of solute in a solution relative to a given mass of solvent. This contrasts with the definition of molarity which is based on a given volume of solution. A commonly used unit for molality is the moles per kilogram (mol/kg). A solution of concentration 1 mol/kg is also sometimes denoted as 1 ...

  8. Ratio - Wikipedia

    en.wikipedia.org/wiki/Ratio

    For example, the ratio 4:5 can be written as 1:1.25 (dividing both sides by 4) Alternatively, it can be written as 0.8:1 (dividing both sides by 5). Where the context makes the meaning clear, a ratio in this form is sometimes written without the 1 and the ratio symbol (:), though, mathematically, this makes it a factor or multiplier.

  9. Percentage solution - Wikipedia

    en.wikipedia.org/wiki/Percentage_solution

    Percentage solution may refer to: Mass fraction (or "% w/w" or "wt.%"), for percent mass. Volume fraction (or "% v/v" or "vol.%"), volume concentration, for percent volume. "Mass/volume percentage" (or "% m/v") in biology, for mass per unit volume; incorrectly used to denote mass concentration (chemistry). See usage in biology. Category: