Question

How to find the empirical formula of ${{\text{C}}_{\text{5}}}{{\text{H}}_{{\text{10}}}}{{\text{O}}_{\text{5}}}$?

Answer 1

We know that a chemical formula is the brief representation of the molecule of substance (compound or element) in terms of the symbols of various elements present in it. Chemical formula is of two types, empirical formula and molecular formula.

Complete step by step answer:
Let’s discuss the empirical formula of a compound. This formula gives the simplest whole number ratio of atoms of various elements present in one molecule of the compound. For example, the empirical formula of ${{\text{H}}_{\text{2}}}{{\text{O}}_{\text{2}}}$ is HO.
Here, the given compound is ${{\text{C}}_{\text{5}}}{{\text{H}}_{{\text{10}}}}{{\text{O}}_{\text{5}}}$. In order to express the empirical formula of ${{\text{C}}_{\text{5}}}{{\text{H}}_{{\text{10}}}}{{\text{O}}_{\text{5}}}$
, we have to take out the common factor 5. Now, the simplest whole number ratio of C, H and O is 1:2:1. So, the empirical formula of ${{\text{C}}_{\text{5}}}{{\text{H}}_{{\text{10}}}}{{\text{O}}_{\text{5}}}$ is ${\text{C}}{{\text{H}}_{\text{2}}}{\text{O}}$.

Additional Information:
Let’s discuss the molecular formula in detail. Molecular formula of a compound gives the actual ratio of the atoms of various elements present in one molecule of the compound. In writing the molecular formula, no common factor is removed and the actual ratio of the atoms is considered. For example, the molecular formula of hydrogen peroxide is ${{\text{H}}_{\text{2}}}{{\text{O}}_2}$. It is to be noted that all compounds are known by their molecular formula and not by empirical formulae. The empirical formulae have only theoretical importance.

Note: The relation between empirical formula and molecular formula is,
Molecular formula=n$\times$empirical formula
Here, n is the common factor or multiplying factor. The value of n may be 1,2,3,4…. etc. In the case of n=1 , then the molecular formula is the same as the empirical formula.