| Author | Message | ||
     Andrew |
Hi Simon, I have a question that's been bugging me. In your chapter on thermodynamics, you say that "Hydrogen will burn in air at concentrations ranging from 4% to 75% by volume" and "Hydrogen will explode in air at ratios of 13% to 59%". When you burn hydrogen, it combines with oxygen to make water. Water is H2O, so that means that it is 2/3 hydrogen and 1/3 oxygen. This also has to be the perfect burning ratio, since there will be no 'ingredients' left over. If I mixed these two gases at this ratio and ignited them, would the mixture burn or explode? And what would this 'perfect ratio' be if I mixed Hydrogen with air (so that if I ignited it in a closed container, there would be no left over Hydrogen or Oxygen)? Thanks! | ||
| Simon Quellen Field (Sfield) |
Dry air is 20.95% oxygen by volume. This goes down as the air gets more humid, but we can use 20% as a nice round figure. That means 1 part oxygen and 4 parts other gasses. Since we have one part oxygen, we add two parts hydrogen to get a perfect mixture. Now there are seven parts in total (1 oxygen, 2 hydrogen, and 4 other gasses). Two of the seven are hydrogen, so we have 28% hydrogen by volume. 28% is between 13% and 59%, so we conclude that it will explode. Removing the other gasses will not affect whether it will explode or not. Thus, a mixture of two parts hydrogen to one part oxygen will explode. | ||
| Andrew |
Ok, that makes sense, thanks for your help! |
