Empirical Formula Question about non-whole numbers  [ENDORSED]

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Swan Ng 1L
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Joined: Fri Sep 25, 2015 3:00 am

Empirical Formula Question about non-whole numbers

Postby Swan Ng 1L » Fri Jul 01, 2016 9:42 pm

I have a question about writing an empirical formula with non-whole numbers. For example, if the empirical formula was C2H1.4C3, am I allowed to multiply the whole empirical formula by 5 in order to make 1.4 from H a whole number? Would that change or effect the answer at all? I know empirical formulas and molecular formulas are supposed to have certain molar masses, so what would be a solution to this problem of having a non whole number in your empirical formula?

Denise Guardado 1C
Posts: 3
Joined: Fri Jun 17, 2016 11:28 am

Re: Empirical Formula Question about non-whole numbers  [ENDORSED]

Postby Denise Guardado 1C » Sat Jul 02, 2016 12:04 am

The definition of an empirical formula is the formula of a compound as the smallest whole number ratio of subscripts of the element in the formula. (provided by 1988 by the Division of Chemical Education of the American Chemical Society, Inc.) So you would need to multiply to get the .4 to the nearest whole number. Usually a problem will give a molar mass for the molecular formula and the empirical formula will have to be multiplied by a whole number to be equal to the molecular formula.

Sara Juarez 1B
Posts: 8
Joined: Tue Nov 24, 2015 3:00 am

Re: Empirical Formula Question about non-whole numbers

Postby Sara Juarez 1B » Sat Jul 02, 2016 6:49 pm

Remember that the empirical and molecular formulas can NOT have decimal/ fraction subscripts. Subscripts represent the number of atom it contains. It is not possible to have 1.5 atoms of N. However it should still contain the smallest whole number of each atom in the formula.

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