What is the molecular formula of HCO2 with the molar mass of 90.0 g/mol?

1 Answer
Nov 15, 2015

Answer:

You have, presumably, the empirical formula, which is the simplest whole number ration defining constituents in a species. The molecular formula is always a multiple of the empirical formula (and the multiple might be one!).

Explanation:

Empirical formula #=# #HCO_2#. The molecular formula (the multiple!) is #(HCO_2)_n#. So #(1.00794 + 12.011+2xx15.999)*g*mol^-1xxn = 90.0*g*mol^-1#.

Clearly #n# #=# #2# and the molecular formula is #(HCO_2)xx2# #=# #??# Is it oxalic acid?