Answer:
Molecular formula naphthalene → C₁₀H₈
Empirical formula naphthalene → C₅H₄
Explanation:
Centesimal composition means that in 100 g of compound we have x g of the element. Therefore in 100 g of naphthalene we have:
93.7 g of C
6.3 g of H
Let's make a rule of three:
In 100 g of naphthalene we have 93.7 g of C and 6.3 g of H
In 128 g of naphthalene we would have:
128 . 93.7 / 100 = 120 g of C
128. 6.3 / 100 = 8 g of H
We convert the mass to moles, by molar mass:
120 g . 1mol / 12 g = 10 moles C
8 g . 1mol/ 1g = 8 moles H
Molecular formula naphthalene → C₁₀H₈
Empirical formula naphthalene → C₅H₄
(The sub-index of each element is divided by the largest possible number)
