Question

What is the empirical formula of C5H10?

Answer 1

The empirical formula of `C_5H_10` is `CH_2`

Explanation:

The empirical formula is the simplest whole number ratio that describes constituent atoms in a species. `C_5H_10` of course can be reduced to `CH_2`.

The molecular formula is always a multiple of the empirical formula (the multiple might be 1). A very useful parameter with molecular formulae is the "degree of unsaturation" concept. An alkane has the general formula `C_nH_(2n+2)` (this could be the same as the empirical formula!). If presented with a molecular formula `C_nH_(2n)` we would say that this molecule has `1^@` of unsaturation. A degree of unsaturation has a double bond (`C=C`, `C=O`, `C=N`) OR a ring to account for the absence of the 2 hydrogens. Simple acetylenes have 2 degrees of unsaturation. Why?