A compound having an empirical formula of #C_3H_4O_3# has a mass of 180 g/mol. What is the molecular formula?

1 Answer
anor277
Jun 4, 2016

#"Molecular formula"# #=# #C_6H_8O_6#

Explanation:

The molecular formula is always a whole number multiple of the empirical formula:

i.e. #"Molecular formula"# #=# #"(Empirical formula)"xxn#

So we need to solve for #n#.

Thus #180*g*mol^-1# #=# #nxx(3xx12.011+4xx1.0079+3xx15.999)*g*mol^-1#
#=# #nxx(88.0)*g*mol^-1#

#n~=2#. Thus #"Molecular formula"# #=# #C_6H_8O_6#.

Of course, the ratio is out a little bit. Such errors are common in the determination of such formulae.

Related questions
See all questions in Empirical and Molecular Formulas
Impact of this question
1583 views around the world
You can reuse this answer
Creative Commons License