3. A compound containing Carbon, Hydrogen and Oxygen gave the following analytical data: Carbon=40.0% , Hydrogen =6.67% and the rest is Oxygen.Calculate the molecular formula of the compound if its molecular mass is180.
Answers
moles of C = 40 / 12 = 3.33 moles
moles of H = 6.67 /1 = 6.67
moles of O = 53.33 / 16 = 3.33 moles
molar ratio of C : H : O = 3.33 : 6.67 : 3.33
= 1 : 2 : 1
Given:
The percentage of carbon in the compound = 40.0%
The percentage of hydrogen in the compound = 6.67%
The molecular mass of the organic compound = 180 g/mol
To Find:
The molecular formula of the organic compound.
Solution:
The percentage of oxygen in the compound = 100 - (40+6.67)%
⇒ % oxygen in the compound = 53.33%
The number of moles of an element in the compound = (Molar mass of organic compound× % of element)÷ (Molar mass of element × 100)
Number of moles of carbon = (180×40)/(12×100) = 72 gm/ 12 = 6 moles
Number of moles of oxygen = (180×53.33)/(16×100) = 96 gm/ 16 = 6 moles
Number of moles of hydrogen = (180×6.67)/(1×100) = 12 gm/ 1 = 12 moles
The ratio of carbon, hydrogen, and oxygen = 6:12:6
The molecular formula = C₆H₁₂O₆
Hence, the molecular formula of the organic compound is C₆H₁₂O₆.