Short answerEasy4 marks
An organic compound ‘X’ contains carbon, oxygen and hydrogen only. The percentage of carbon and hydrogen are 47.4% and 10.5% respectively. The relative molecular mass of ‘X’ is 76. Find the empirical formula and the molecular formula of ‘X’. [Atomic weight: C = 12, O = 16, H = 1]
Topic: Mole concept, gas volumes and stoichiometry
Previous-year question practice database
Answer
Exam answer
Empirical formula = C₃H₈O₂; molecular formula = C₃H₈O₂.
Explanation
Oxygen = 42.1%. Relative mole ratio C:H:O = 47.4/12 : 10.5/1 : 42.1/16 = 3.95:10.5:2.63 = 3:8:2. Empirical formula mass = 76, equal to molecular mass.
More from Mole Concept and Stoichiometry
The electronic configuration of an element is 2,8,2. The hydroxide of this element can produce ............... hydroxyl ions per molecule.2026What volume of carbon dioxide is produced at STP when 5 litres of propane is burnt completely according to the equation given below?
C₃H₈ + 5O₂ → 3CO₂ + 4H₂O2026The relative molecular mass of a substance expressed in grams.2026The volume occupied by 8 grams of oxygen gas at STP is ............... litres. [5.6 / 8.96] [Atomic weight of O = 16]2026Equal volumes of ammonia gas and chlorine gas are kept in two different containers under the same conditions of temperature and pressure.
Find the number of molecules contained in chlorine gas when the mass of ammonia is 34 g.
[Atomic weight: Cl=35.5, H=1, N=14]2026The type of reaction that occurred is ............... . (addition / substitution)2026