A mixture was prepared in a 500 mL reaction vessel from 227 mL of O₂ (measured at 17.6 C and 640 torr) and 637 mL of H₂ (measured at 40.6 C and 1390 torr). The mixture was ignited and the H₂ and O₂ reacted to form water. What was the final pressure inside the reaction vessel after the reaction was over if the temperature was held at 129 C? P =