Answer to Question #308940 in Chemistry for user1357

Question

If the empirical formula of a compound is P₂O₃, and it has a molecular weight equal to 220 g/mol, what is its molecular formula?

Answer 1

Solution:

Empirical formula = P₂O₃

Molar mass of P₂O₃ = 2×Ar(P) + 3×Ar(O) = 2×31 + 3×16 = 110 (g/mol)

Molecular formula = (P₂O₃)_n

Molar mass of (P₂O₃)_n is 220 g/mol

n = (Molecular formula / Empirical formula) = (Molar mass of (P₂O₃)_n / Molar mass of P₂O₃)

n = 220 / 110 = 2

Therefore,

Molecular formula = (P₂O₃)₂ = P₄O₆

Answer: The molecular formula of a compound is P₄O₆