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l 3 n −1 In chemistry and related fields, the molar volume , symbol V m , [ 1 ] or V ~ {\displaystyle {\tilde {V}}} of a substance is the ratio of the volume ( V ) occupied by a substance to the amount of substance ( n ), usually at a given temperature and pressure .
Molar concentration or molarity is most commonly expressed in units of moles of solute per litre of solution. [2] For use in broader applications, it is defined as amount of substance of solute per unit volume of solution, or per unit volume available to the species, represented by lowercase : [3]
The standard unit is the meter cubed per kilogram (m 3 /kg or m 3 ·kg −1). Sometimes specific volume is expressed in terms of the number of cubic centimeters occupied by one gram of a substance. In this case, the unit is the centimeter cubed per gram (cm 3 /g or cm 3 ·g −1). To convert m 3 /kg to cm 3 /g, multiply by 1000; conversely ...
At standard mean sea level it specifies a temperature of 15 °C (59 °F), pressure of 101,325 pascals (14.6959 psi) (1 atm), and a density of 1.2250 kilograms per cubic meter (0.07647 lb/cu ft). It also specifies a temperature lapse rate of −6.5 °C (−11.7 °F) per km (approximately −2 °C (−3.6 °F) per 1,000 ft).
The litre was also used in several subsequent versions of the metric system and is accepted for use with the SI, [3] although not an SI unit—the SI unit of volume is the cubic metre (m 3). The spelling used by the International Bureau of Weights and Measures is "litre", [ 3 ] a spelling which is shared by most English-speaking countries.
The mole is widely used in chemistry as a convenient way to express amounts of reactants and amounts of products of chemical reactions. For example, the chemical equation 2 H 2 + O 2 → 2 H 2 O can be interpreted to mean that for each 2 mol molecular hydrogen (H 2) and 1 mol molecular oxygen (O 2) that react, 2 mol of water (H 2 O) form.
The cubic metre (in Commonwealth English and international spelling as used by the International Bureau of Weights and Measures) or cubic meter (in American English) is the unit of volume in the International System of Units (SI). [1] Its symbol is m 3. [1] It is the volume of a cube with edges one metre in length.
On 7 April 1795, the metric system was formally defined in French law using six units. Three of these are related to volume: the stère (1 m 3) for volume of firewood; the litre (1 dm 3) for volumes of liquid; and the gramme, for mass—defined as the mass of one cubic centimetre of water at the temperature of melting ice. [10]