Determine the empirical and molecular formulas of each of the following substances:
(a) Ibuprofen, a headache remedy, contains 75.69$\% \mathrm{C}$ , $8.80 \% \mathrm{H},$ and 15.51$\% \mathrm{O}$ by mass and has a molar mass of 206 $\mathrm{g} / \mathrm{mol} .$
(b) Cadaverine, a foul-smelling substance produced by the action of bacteria on meat, contains 58.55$\% \mathrm{C}$ , $13.81 \% \mathrm{H},$ and 27.40$\% \mathrm{N}$ by mass; its molar mass is 102.2 $\mathrm{g} / \mathrm{mol}$
(c) Epinephrine (adrenaline), a hormone secreted into the bloodstream in times of danger or stress, contains 59.0$\%$ C, $7.1 \% \mathrm{H}, 26.2 \% \mathrm{O},$ and 7.7$\% \mathrm{N}$ by mass; its molar mass is about 180 amu.