Question

64g of an organic compound contains carbon, of hydrogen and the rest is $ 64g $ oxygen what is the empirical formula of the compound?

Answer 1

Hint: In the above-given question we first need to find out the formula of the compound by calculating the number of atoms included of carbon, hydrogen, oxygen. Then we will find out the simplest ratio of the molecular formula to find out the empirical formula.

Complete step by step answer:
The empirical formula is the simplest ratio of the molecular formula of the compound. In an organic compound, there are three main atoms that are carbon, hydrogen, oxygen. We are provided with the total molecular weight of the compound that is $ 64g $ , now the total mass of the carbon in the compound is $ 24g $ , the atomic mass of carbon is $ 12g $ , therefore the total number of atoms f carbon present is;
 $ nC = 24/12 $
 $ \Rightarrow $ $ nC = 2 $
Now the total mass of the hydrogen in the compound is $ 8g $ , the atomic mass of carbon is $ 1g $ , therefore the total number of atoms of hydrogen present is;
 $ nH = 8/1 $
 $ \Rightarrow $ $ nH = 8 $
The only remaining element is oxygen, to find out the mass of oxygen we need to subtract the sum of the mass of carbon and hydrogen from the total molecular mass of the given formula;
 $ {m_O} = 64 - ({m_C} + {m_H}) $
 $ \Rightarrow $ $ {m_O} = 64 - (24 + 8) $
 $ \Rightarrow $ $ {m_O} = 64 - 32 $
 $ \Rightarrow $ $ {m_O} = 32 $
The total mass of oxygen present in the formula is $ 32g $ , and the atomic mass of oxygen is $ 16g $ , therefore the total number of atoms of oxygen present is;
 $ nO = 32/16 $
 $ \Rightarrow $ $ nO = 2 $
By the above calculation, we can conclude that the molecular formula of the compound is $ {C_2}{H_8}{O_2} $ .
To find out the empirical formula we need to divide the formula by the simplest factor that is 2, on doing so we get $ C{H_4}O $ .
The empirical formula of the compound is $ C{H_4}O $

Note:
Organic compounds are generally formed by hydrogen, carbon and oxygen. Compounds which are considered to have central atoms as carbon and there is the bonding between two carbon atoms may be single, double or triple bonds.