A compound is found to contain 1.32 moles of Li, 0.66 moles of Se, and 2.64 moles of O. What is the empirical formula of the compound?

1 Answer
Jan 21, 2016

Answer:

#Li_2SeO_4#

Explanation:

The empirical formula is the SIMPLEST whole number ratio that defines constituent atoms in a species. If we divide the given molar quantities, by the LEAST molar quantity (that of selenium), we get the empirical formula above.

#Li_2SeO_4# is clearly ionic, and non-molecular (#SeO_4^(2-)# is an analogue of the sulfate ion, #SO_4^(2-)#). Typically with these problems you are asked to provide the empirical formula, and then asked to provide the molecular formula given a molecular mass. The molecular formula is always a multiple of the empirical formula: #MF# #=# #(EF)_n#. Of course, the molecular formula might be the same as the empirical formula; in which case #n# #=# #??#