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Synonym: Molar Mass = Molecular Weight

Material property defined as the mass of a given substance (chemical element or chemical compound) contained within one mole of the substance.

Symbol	Dimension	SI units	Oil metric units	Oil field units	Additional
	M N^-1	kg/mol	kg/mol	lb_m / mol = 0.45359237 kg/mol	g/mol = 0.001 kg/mol

It measures as ratio of substance mass to amount of substance :

M = \frac{m}{\nu}

It relates to molecular mass and Avogadro constant as:

M = m_u \cdot N_A

M = \frac{m}{\nu} =  m  \cdot \frac{N_A}{N} = m_u \cdot N_A

where

number of molecules in a substance of amount

The molar mass of a mixture is:

M = \sum_k M_k \cdot x_k

where

	molar mass of the k-th mixture component
	mole fraction of the k-th mixture component

M = \frac{m}{\nu} = \frac{N_A}{N} \cdot m = \frac{N_A}{N} \cdot \sum_k m_{u,k} \cdot N_k  = \frac{N_A}{N} \cdot \sum_k \frac{M_k}{N_A} \cdot N \cdot x_k  =\sum_k M_k \cdot x_k

where

	number of particles in the k-th mixture component
	total number of particles in mixture
	molecular mass of the particles in the k-th mixture component