Mixtures of helium and oxygen are used for scuba diving. For a particular dive, 46 liters of O2 at 25 degrees celsius and 1.0 atm and 12 liters of He at 25 degrees celsius and 1.0 atm are pumped into a tank with a volume of 5.0 liters. Calculate the partial pressure of each gas and the total pressure in the tank at 25 degrees celsius. (Determine moles of each gas first.)