One type of gas mixture used in anesthesiology is a 50%/50% mixture (by volume) of nitrous oxide (n2o) and oxygen (o2), which can be premixed and kept in a cylinder for later use. because these two gases don’t react chemically at or below 2000 psi, at typical room temperatures they form a homogeneous single gas phase, which can be considered an ideal gas. if the temperature drops below -6âˆ˜c, however, n2o may begin to condense out of the gas phase. then any gas removed from the cylinder will initially be nearly pure o2; as the cylinder empties, the proportion of o2 will decrease until the gas coming from the cylinder is nearly pure n2o. in a hospital, pure oxygen may be delivered at 50 psi (gauge pressure) and then mixed with n2o. part a what volume of oxygen at 20âˆ˜c, and 50 psi (gauge pressure) should be mixed with 2.8 kg of n2o to get a 50%/50% mixture by volume at 20âˆ˜c?