Question

A compound is19.3% Na, 26.9% s, and 53.8% O. It formula mass is238:g/mol.What is the molecular formula​

Answer 1

Answer:

Na = 19.3 g

S = 26.9 g

O = 53.8 g

Na — 19.3 g / 22.99 g/mol = 0.839 mol / 0.839 mol = 1 mol

S — 26.9 g / 32.07 g/mol = 0.839 mol / 0.839 mol = 1 mol

O — 53.8 g / 16.00 g/mol = 3.36 mol / 0.839 mol = 4 mol

Empirical Formula: NaSO4; with a molar mass of 142.04 g/mol

The ratio between the formula mass and the empirical mass is 1.68 ~ 2

Thus, the molecular formula is Na2S2O8.