Question: what is the chemical composition of urine?
Answer: On an elemental level, human urine contains 6.87 g/L carbon, 8.12 g/L nitrogen, 8.25 g/L oxygen, and 1.51 g/L hydrogen. The exact proportions vary with individuals and with factors such as diet and health. In healthy persons, urine contains very little protein and an excess is suggestive of illness.