Question

A compound with the empirical formula NPCl2 was found in a subsequent experiment to have a molar mass of 347.64 g/mol. What is the molecular formula of the compound?

Answer 1

Molecular Formula = N₃P₃Cl₆

Step-by-step explanation:

Molecular formula is calculated by using following formula,

Molecular Formula = n × Empirical Formula ---- (1)

Also, n is given as,

n = Molecular Weight / Empirical Formula Weight

Molecular Weight = 347.64 g.mol⁻¹

Empirical Formula Weight = 1 (N) + 1 (P) + 2 (Cl) = 115.88 g.mol⁻¹

So,

n = 347.64 g.mol⁻¹ ÷ 115.88 g.mol⁻¹

n = 3

Putting Empirical Formula and value of "n" in equation 1,

Molecular Formula = 3 × NPCl₂

Molecular Formula = N₃P₃Cl₆