What is Empirical formula and Molecular formula with egs.

Asked by  | 9th Jun, 2008, 07:34: PM

Expert Answer:

Elemental analysis is a useful qualitative analysis technique since it allows us to check if a sample is consistent with a given molecular formula. For instance, suppose we believe our sample is benzene (C6H6). We can compare the following:

  • The empirical formula (CH) obtained from the molecular formula of benzene (C6H6)
  • The empirical formula obtained from a elemental analysis of the sample

If the two empirical formulae do not agree, then the sample is not benzene. If the formulae agree, then our sample may be benzene. (Remember that more than one molecule can have the sample empirical formula. For instance, both benzene (C6H6) and acetylene (C2H2) have the empirical formula CH, so a sample whose elemental analysis yields CH as an empirical formula could be benzene, acetylene, or some other molecule with a 1:1 ratio between C and H.)

The empirical formula is the simplest formula for a compound. A molecular formula is the same as or a multiple of the empirical formula, and is based on the actual number of atoms of each type in the compound. For example, if the empirical formula of a compound is C3H8 , its molecular formula may be C3H8 , C6H16 , etc.

Answered by  | 10th Jun, 2008, 05:20: AM

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