In
chemistry, the
mass concentration ![](http://bis.babylon.com/?rt=GetFile&uri=!!ARV6FUJ2JP&type=0&index=577)
(or
![](http://bis.babylon.com/?rt=GetFile&uri=!!ARV6FUJ2JP&type=0&index=1786)
) is defined as the
mass of a constituent
![](http://bis.babylon.com/?rt=GetFile&uri=!!ARV6FUJ2JP&type=0&index=1382)
divided by the
volume of the mixture
![](http://bis.babylon.com/?rt=GetFile&uri=!!ARV6FUJ2JP&type=0&index=896)
:
For a pure chemical the mass concentration equals its
density (mass divided by volume); thus the mass concentration of a component in a mixture can be called the density of a component in a mixture. This explains the usage of
ρ (the lower case Greek letter
rho), the symbol most often used for density.