The occupational safety and health administration has set the limit on the maximum percentage of carbon dioxide (co) in air a worker can breathe at 0.500% by mole. if dry ice (solid co2) is sublimating (becoming a gas) in a room at a rate of 0.500 mol/min, what is the minimum rate that fresh air has to be supplied to the room so that the concentration of co2 in the room doesn't exceed 0.500% by mole? assume the room is well mixed, and the volume of the solid dry ice does not change. number mol air/min what is the percent by mass of oxygen in a gaseous mixture whose molar composition is 0.500% co2 and 99.500% air? the composition of air is 21% mole o2, 79% mole n2, and has an average molar mass of 29.0 g/mol. number % o, by mass