I have corrected the bit which said air at sea level contains 20.5% oxygen by dry weight. First of all, the concept of weighing air is a bit pointless as the only way of doing this meaningfully would be to liquify huge volumes of gas. Secondly, the concept of partial pressure is related to the 'concentration', more usefully, the proportion of gasses in relation to the total mixture, not the total weight. So, for a 1:1 mixture of xenon and hydrogen - two gasses with a huge difference in molecular weights - at a pressure of 100kPa, the partial pressures for both gasses are 50kPa. Mark ong 11:41, 11 October 2006 (BST)
- Yes, dry air, volume. "Composition" leaves it hanging a little though. Weighing air isn't that difficult, you can feel the difference between a cylinder that is full and one that is empty, although it is much easier to work out the volume remaining by measuring the pressure than the weight. Midgley 17:33, 11 October 2006 (BST)
Although a cylinder of gas is pressurised and therefore liquid rather than gaseous and so the Gas Laws don't apply? Mark ong
Flying while pregnant
Discussed in DNUK http://www.doctors.net.uk/Forum/viewPost.aspx?forum_id=12&post_id=2442161 with several links mentioned.
SIze of the probem?
514 emergency calls made by UK airlines in 2007 due to medical emergencies. Midgley 23:15, 9 April 2008 (BST)