Given density in #"g/L"#, how to calculate molar volume?

1 Answer
Aug 29, 2017

#barV = M/D#

#D# in #"g/L"#
#M# in #"g/mol"#


You can do that with a unit conversion. In principle, if you can convert from the density to the molar volume, you can convert from the molar volume to the density, so I will show the former case.

Given a density in #"g"/"L"#, you're almost there already. A molar volume is known to have typical units of #"L"/"mol"#. So, take the reciprocal to get:

#=> "L"/"g"#

Now, since you want to cancel out #"g"# and have #"mol"^(-1)# remaining, simply multiply by the molar mass.

#"L"/cancel"g" xx cancel"g"/"mol" = "L"/"mol"# #color(blue)(sqrt"")#

What we've just done can be written in variables.

Given a density #D# ALREADY in #"g"/"L"# and a molar mass in #"g"/"mol"#, the molar volume #barV# is:

#color(blue)(barV = M/D)#