User:Milton Beychok/Sandbox: Difference between revisions
Jump to navigation
Jump to search
imported>Milton Beychok No edit summary |
imported>Milton Beychok No edit summary |
||
Line 1: | Line 1: | ||
The '''molar volume''' (symbol ''V''<sub>m</sub>) is the [[volume (science)|volume]] occupied by one [[mole (unit)|mole]] of a substance ([[chemical element]] or [[chemical compound]]) at a given [[temperature]] and [[pressure]].<ref name="GreenBook">{{GreenBookRef2nd|page=41}}</ref> It is equal to the [[molecular mass]] (''M'') divided by the [[density (chemistry)|density]] (''ρ''): | |||
::<math>V_{\rm m} = {M\over\rho}</math> | |||
It has an [[SI unit]] of cubic [[metre]]s per mole (m<sup>3</sup>/mol).<ref name="GreenBook"/> However, molar volumes are often expressed as cubic metres per 1,000 moles (m<sup>3</sup>/kmol) or cubic decimetres per mol (dm<sup>3</sup>/mol) for gases and as centimetres per mole (cm<sup>3</sup>/mol) for liquids and solids. | |||
If a substance is a mixture containing ''N'' components, the molar volume is calculated using: | |||
::<math>V_{\rm m} = \frac{\displaystyle\sum_{i=1}^{N}x_{i}M_{i}}{\rho_{mixture}}</math> | |||
where ''x<sub> i</sub>'' is the [[mole fraction]] of the ith component. | |||
== Ideal gases == | |||
The ideal gas equation can be rearranged to give an expression for the molar volume of an ideal gas: | |||
::<math>V_{\rm m} = {V\over{n}} = {{RT}\over{P}}</math>. | |||
== References == |
Revision as of 18:36, 10 January 2010
The molar volume (symbol Vm) is the volume occupied by one mole of a substance (chemical element or chemical compound) at a given temperature and pressure.[1] It is equal to the molecular mass (M) divided by the density (ρ):
It has an SI unit of cubic metres per mole (m3/mol).[1] However, molar volumes are often expressed as cubic metres per 1,000 moles (m3/kmol) or cubic decimetres per mol (dm3/mol) for gases and as centimetres per mole (cm3/mol) for liquids and solids.
If a substance is a mixture containing N components, the molar volume is calculated using:
where x i is the mole fraction of the ith component.
Ideal gases
The ideal gas equation can be rearranged to give an expression for the molar volume of an ideal gas:
- .