Answer:
The hydrocarbon has a molecular formula of C3H3
Explanation:
Step 1: Data given
Suppose the mass of the compound is 100 grams
A hydrocarbon contains:
⇒ 92.3 % carbon = 92.3 grams
⇒ 7.7 % hydrogen = 7.7 grams
Molar mass of the compound is 40 g/mol
Molar mass of carbon = 12.01 g/mol
Molar mass of hydrogen = 1.01 g/mol
Step 2: Calculate moles
Moles = mass / molar mass
Moles carbon = 92.3 grams / 12.01 g/mol
Moles carbon = 7.69 moles
Moles hydrogen = 7.70 grams / 1.01 g/mol
Moles hydrogen = 7.62
Step 3: Calculate mol ratio
We divide by the smallest amount of moles
Carbon: 7.69/7.62 = 1
Hydrogen: 7.62/7.62 = 1
The empirical formula is CH
The molar mass is 13.02 g/mol
Step 4: Calculate the molecular formula
n = 40 g/mol / 13.02 g/mol
n ≈ 3
We need to multiply the empirical formula by 3 to get the molecular formula
Molecular formula = 3*(CH) = C3H3
The hydrocarbon is C3H3
