Template talk:Concentration and density

Density versus concentration

mass concentration C_ms = m_s·V^-1 for sample s in a mixture, where V_s < V (BEC 2020.1).

Defining density generally as (1) an extensive quantity divided by volume of the sample: mass density or mass concentration is mass of the sample per volume, m_s·V^-1 [kg·L^-1]; electric charge density Q·V^-1 [C·L^-1]; energy density [J·m^-3]; radiant energy density is radiant energy per volume [J·m^-3].

Density is (2) an extensive quantity divided by area: Electric current density is current divided by area, I·A^-1 [C·m^-2].

Thus the sample mass concentration is C = m_X·V^-1 [kg·m^-3], the mitochondrial concentration is C_mtE = mtE·V^-1 [mtEU·m^-3], whereas the specific mitochondrial density is D_mtE = mtE·m_X^-1 [mtEU·kg^-1], and the mitochondrial content per object X is mtE_NX = mtE·N_X^-1 [mtEU·x^-1] (BEC 2020.1).

Number density of entities or count concentration is numbers of elementary entities per volume, C_X = N_X·V^-1 [x·m^-3].