Question

A compound contains 85.7% carbon and 14.3% hydrogen and has a molar mass of 98.0 g/mol. What is the (I) molecular formula? (II) empirical formula?

A) (I) C4H7; (II) CH
B) (I) C6H12; (II) CH₂
C) (I) C5H10; (II) CH₂
D) (I) C3H6; (II) CH3

Answer 1

The molecular formula is C5H10 and the empirical formula is CH2.

Step-by-step explanation:

To determine the molecular formula of a compound, we need to compare the molar mass of the compound with the empirical formula mass.

The empirical formula can be determined by converting the percentages of carbon and hydrogen into moles and finding the ratio. In this case, the molar mass of the compound is 98.0 g/mol, which is close to twice the empirical formula mass. Therefore, the molecular formula is twice the empirical formula, giving us (I) C5H10 as the molecular formula.

To find the empirical formula, we need to determine the simplest whole number ratio of atoms. In this case, the simplest ratio is CH2. So, the empirical formula is (II) CH2.