Heliox is a helium-oxygen mixture that may be used in scuba tanks for divers working at great depths. it is also used medically as a breathing treatment. a 7.25-l tank holds helium gas at a pressure of 1347 psi. a second 7.25-l tank holds oxygen at a pressure of 358.1 psi. the two gases are mixed in a 7.25-l tank. if the temperature remains the same throughout the process, what is the pressure of the gas mixture in the tank? assume ideal gas behavior.