Question Detail
Question
A compound is found to contain 85.7% carbon and 14.3% hydrogen by mass. Its molecular weight is 56.1 g/mol. What is its molecular formula? (C=12, H=1)
Correct Answer
Option D is the correct answer.
Detailed Explanation
Empirical formula: C = 85.7/12 = 7.14, H = 14.3/1 = 14.3. Ratio = 7.14/7.14 : 14.3/7.14 = 1:2 → CH₂ (mass 14). n = 56.1/14 = 4. So molecular formula = C₄H₈.
Hint
Find the empirical formula mass, then determine how many times it fits into the given molecular weight.