Empirical and Molecular Formula Interactive Widget

Two completely different molecules can share the exact same empirical formula

CH₂O is the empirical formula for glucose, formaldehyde, and acetic acid — wildly different compounds with nothing in common except a 1:2:1 atom ratio. Understanding the gap between empirical and molecular formulae is how you decode real exam combustion data. Drag the slider to scale up from empirical to molecular formula.

Formula Scaler n = 1 (empirical)
Scale factor × empirical = molecular
CH₂O × 1 = CH₂O
Scale factor (n)
1 2 3 4 5 6
Empirical mass
30
Molecular mass
30
Glucose (C₆H₁₂O₆, molar mass 180) and formaldehyde (CH₂O, molar mass 30) both reduce to the same empirical formula: CH₂O. The empirical mass is 30 g/mol (12 + 2 + 16), so glucose's molecular formula is exactly 6 empirical units stacked together — 180 ÷ 30 = 6, so multiply every subscript by 6. This is why you need both percentage composition and molar mass to find the real formula: percentage gets you the ratio (empirical), molar mass tells you the scaling factor. The worked method: from %C, %H, %O → divide by atomic mass → divide all by smallest → whole-number ratio = empirical → then molar mass ÷ empirical mass = n, the multiplier that gets you from empirical to molecular.
Know This
The empirical formula is the simplest ratio; the molecular formula is the real count, always an integer multiple of the empirical.