Exercise 6 | The periodic table and Chemical Periodicity

Find the empirical formula of a compound which is 31.9% K, 28.9% Cl and 39.2% O.

Empirical formula is KXClYO⇒ MKxClyOz = X MK + Y MCl + Z MO = 39.1 X + 35.4 Y + 16.0 Z

%K = 39.1 X / MKxClyOz = 0.319
%Cl = 35.4 Y / MKxClyOz = 0.289
%O = 16.0 Z / MKxClyOz = 0.392

If  X = 1, MKxClyOz = 122.57 g.mol-1 and Y = 1 and Z = 3.

X, Y and Z are the smallest whole number possible, so the empirical formula of this compound is KClO3