what is mean by Molar volume of a gas
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Answer:
The molar volume, symbol Vm,[1] is the volume occupied by one mole of a substance (chemical element or chemical compound) at a given temperature and pressure. It is equal to the molar mass (M) divided by the mass density (ρ). It has the SI unit cubic metres per mole (m3/mol),[1] although it is more practical to use the units cubic decimetres per mole (dm3/mol) for gases and cubic centimetres per mole (cm3/mol) for liquids and solids.
Definition
Change in volume with increasing ethanol.
The molar volume of a substance is defined as its molar mass divided by its density:
{\displaystyle V_{\rm {m}}={M \over \rho }} V_{\rm m} = {M\over\rho}.
If the sample is a mixture containing N components, the molar volume may be approximated as the sum of the molar volume of its individual components, using the density of the mixture.
{\displaystyle V_{\rm {m}}={\frac {\displaystyle \sum _{i=1}^{N}x_{i}M_{i}}{\rho _{\mathrm {mixture} }}}} V_{\rm m} = \frac{\displaystyle\sum_{i=1}^{N}x_{i}M_{i}}{\rho_{\mathrm{mixture}}}.
However, many liquid–liquid mixtures, for instance mixing pure ethanol and pure water, experience contraction or expansion upon mixing. This effect is called "excess volume".