Chapter 10, Problem 49QAP

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 $\left(d=0.877\text{g}/\text{mL}\right)$ freezes at 3.03°C. Pure benzene $\left(k_f=5.10°\text{C}/m\right)$ freezes at 5.500C. What are the simplest and molecular formulas for caffeine?