Question

What is the empirical formula of H2O2?

Answer 1

The empirical formula is the simplest whole number ratio that defines constituent atoms in a species.

Explanation:

Given the above definition the empirical formula of hydrogen peroxide is simply `OH`. Note that the molecular formula is ALWAYS a multiple of the empirical formula. That is `(EF)_n = MF`; where `EF, MF` are empirical and molecular formulae respectively and `n` is a whole number (what does `n` equal here?).

What are the empirical formulae of benzene, ethylene, and acetylene; the molecular formulae are `C_6H_6`, `H_2C=CH_2`, and `HC-=HC`, respectively.

Answer 2

The empirical formula for the molecular formula `"H"_2"O"_2"` is `"HO"`.

Explanation:

The empirical formula of a compound is the lowest whole number ratio of elements in the compound. This ratio becomes the subscripts for the empirical formula.

The molecular formula `"H"_2"O"_2"` is a multiple of the empirical formula. We can know this because the ratio of `"2H":2"O"` is not the lowest whole number ratio. By dividing the subscripts by `2`, we can determine the lowest whole number ratio, which is `"1H":1"O"`. Therefore, the empirical formula for `"H"_2"O"_2"` is `"HO"`.

Sometimes the molecular and empirical formulas are the same.