Caffeine is made up of 49.5% C, 5.2% H, 16.5% O, and 28.9% N. A solution made up of 8.25 g of caffeine and 100.0 mL of benzene (d=0.877 g/mL) freezes at 3.03 C. Pure benzene (Kf=5.10 C/m) freezes at 5.50 C. What are the simplest and molecular formulas for caffeine?