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1) Phentyfloroform contains 57.54% C, 3.45% H, and 39.01% F. What is its empirical formula?
2) The active ingredient in chocolate is theobromine; a sample was analyzed and determined to be composed of:
147.0 g C 14.0 g H 56.0 g O 98.0 g N
a) Determine the % composition for each element.
b) Determine the empirical formula for theobromine.
c) The molecular weight of theobromine is known to be 180.0 g/mole. What is the molecular formula?
3) A compound containing 52.2% C, 13.0% H and 34.8% O has an observed molar mass of 91.6 g/mol. Determine (a) the empirical formula, (b) the molecular formula, (c) the exact molar mass of the compound.
4) 9.83 mg of an unknown chemical compound containing only C, H, and O is submitted for elemental analysis. After combustion, 23.26 mg of CO2 and 9.52 mg of H2O are produced. What are the percent compositions of C, H, and O in the sample?
5) Compound X (molecular weight = 84) has the following percent composition:
Na = 27.38; H = 1.19; O = 57.15; C = 14.28
Determine the empirical and molecular formula for X.