Question

an organic compound containing oxygen, carbon, hydrogen, nitrogen contains 20% Carbon, 6.7% hydrogen, and 46.67%. its molecular weight was found to be 60. find the molecular formula of the compound
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Answer 1

Answer:

$\bigstar{\bold{Molecular\:formula=CH_4N_2O}}$

Explanation:

$\Large{\underline{\underline{\bf{Given:}}}}$

• % of Nitrogen (N) = 46.67%
• % of Carbon(C) = 20 %
• % of Hydrogen (H) = 6.7%
• Molecular weight of the compund = 60

$\Large{\underline{\underline{\bf{To\:Find:}}}}$

→ Here we have to find the simplest whole number ratio of all the elemnts present in the compound.

→ First we have to find the number of moles of each element.

→ Number of moles of an element is given by

 Number of moles= Given mass/Molar mass

→ Number of moles of nitrogen = 46.67/14

  Number of moles of nitrogen = 3.33 moles

→ Number of moles of carbon = 20/12

  Number of moles of carbon = 1.67 moles

→ Number of moles of hydrogen = 6.7/1

  Number of moles of hydrogen = 6.7 moles

→ Now the % composition of oxygen is given by,

  % of Oxygen (O) = 100 - ( 20 + 6.7 + 46.67)

  % of oxygen = 100 - 73.37

  % of oxygen = 26.63 %

→ Number of moles of oxygen = 26.63/16

  Number of moles of oxygen = 1.66 moles

→ Now we have to find the whole number ratio,

→ Whole number ratio of nitrogen = 3.33/1.66

   Whole number ratio of nitrogen = 2

→ Whole number ratio of carbon = 1.67/1.66

  Whole number ratio of carbon = 1

→ Whole number ratio of hydrogen = 6.7/1.66

  Whole number ratio of hydrogen = 4

→ Whole number ratio of oxygen = 1.66/1.66

  Whole number ratio of oxygen = 1

→ Hence the empirical formula of the compund is CH₄N₂O

→ Now the molecular mass of the compund is given by

  Molecular mass = 12 + 4 × 1 + 14 × 2 + 16

  Molecular mass = 60

→ n = molecular weight/molecular mass

  n = 60/60

  n = 1

→ Hence molecular formula of the compund is CH₄N₂O

 $\boxed{\bold{Molecular\:formula=CH_4N_2O}}$