Question

You are the medical examiner at the scene of a murder at a restaurant. There is a
suspicion that the victim was poisoned. Their blood contained the following %
composition 80.66%-c, 7.39%-H, 9.39 %-N, and 2.68%-o Which of the following
compounds was the cause of the murder?

Answer 1

The compound : C₄₀H₄₄N₄O

Further explanation

The empirical formula is the smallest comparison of atoms of compound =mole ratio of the components

The principle of determining empirical formula

• Determine the mass ratio of the constituent elements of the compound.  

• Determine the mole ratio by dividing the percentage by the atomic mass

The mol ratio of composition : C : H : N : O

$\tt \dfrac{80.66}{12}\div \dfrac{7.39}{1}\div \dfrac{9.39}{14}\div \dfrac{2.68}{16}\\\\6.722\div 7.39\div 0.671\div 0.1675\rightarrow divide~by~smallest(0.1675)\\\\40\div 44\div 4\div 1$