Pharaoh definition, meaning, English dictionary, synonym, see also 'Pharaoh ant',Pharaoh's ant',Pharaoh ant',Pharos', Reverso dictionary, English definition, English vocabulary Translation Context
The intake to this ventilation. system must be near the floor. (Chlorine as a gas is. 2.5 times heavier than air.) Exhaust Rate The exhaust system must be able to exchange the air. in the room every three to four minutes.
So any gas with a MW less than 29 will be lighter than air. That, by the way, includes nitrogen! Methane has a MW of 16; helium is 4; hydrogen is 2. I can't think of any other compound or element that's a gas at STP that has a MW less than 29. Afterthought: OK, neon has a molecular weight of 20, which is lighter than air. Ammonia (gas at room temp) has a MW of 17.