Empirical and Molecular Formula - Problem Set
1. Allicin is the compound responsible for the characteristic smell of garlic. An analysis of
the compound gives the following percentage composition: 44.4% C, 6.21% H, 39.5% S
and 9.86% O.
a) Calculate the empirical formula of allicin
b) If the molar mass of allicin is 162, find the molecular formula of allicin
2. A 319.224g sample of a substance contains 128 g O, 127.092 g Cu, and 64.132 g S. What
is the empirical formula of this substance?
3. A compound containing only nitrogen and sulfur is 69.6% sulfur by mass and has a
molecular mass of 184. Find both the empirical and molecular formulas of this
compound.
4. A compound called vinyl chloride has a composition of 38.43% carbon, 4.838%
hydrogen, and 56.72% chlorine. When vinyl chloride is polymerized (many single units
linked together to form a long chain) under certain conditions, a white solid called
polyvinyl chloride is formed with molecular mass of 23875. What is the molecular
formula of polyvinyl chloride ?
5. Determine the molecular formula of a compound containing 85.7% carbon and 14.3 %
hydrogen by mass. The molar mass of the compound is 84.0.
6. Many compounds have the empirical formula of CH2O. Here are the molecular weights
of three: 1) 30.0 2) 60.0 3) 180.0 Determine the molecular formula for each.
7. Caffeine has the following percent composition: carbon 49.48%, hydrogen 5.19%, oxygen
16.48% and nitrogen 28.85%. Its molecular mass is 194.19 g in one mole. What is its
molecular formula?
8. A Uranium oxide is 84.7% U by mass. What is the empirical formula of this compound?