Re: Just add water

I didn't believe it until I checked it out myself.  Yup, it works.
But why stop at water (OH2)?  Let your imagination run wild.

Ammonia (NH3)
  b.p. -28 deg. F (sorry about the English units, that's what
                   the book has).
  Density, liq:  42.6 lb/ft^3  =  .682 tons/m^3
  %wt of Hydrogen:  17.65%     (3/(14+1+1+1))
  Density of Hydrogen:  .120 tons/m^3

  About 1.70 times the hydrogen in the same space.
  (Density of H (LH2) is about .0708 tons/m^3)
  (Water worked out to about 1.57 times the hydrogen)


Methane (CH4)
  b.p.  -164 deg. C  (yup, these are in SI)
  Density, liq:  .5547 (not sure about this.  The table
                        also says .466 next to the gas
                        phase, but that is awfully dense
                        for a gas).
  %wt of Hydrogen:  25%     (4/(12+1+1+1+1))
  Density of Hydrogen:  .1387 tons/m^3

  About 1.96 times the hydrogen in the same space!
  Wow, almost doubled capacity!

Hmm, just found ammonia on another chart that says its
liquid density is .7710 tons/m^3 which would give a H
density of .1358 tons/m^3 or 1.92 times capacity.

A quick check into the thermodynamic properties of
these three (water, ammonia , methane) says:

143  kJ/mole to split H2O into H2 and O2
15.4 kJ/mole to splie NH3 into N2 and H2
18.7 kJ/mole to split CH4 into H2 and C(graphite)

Looks like it should be easier to extract hydrogen from
methane and ammonia than water.  Anyone know for sure?

I suspect methane is about the best you can do since it uses
four bonds with hydrogen--the normal maximum.  Of course, there
might be some superdense liquid or really messed up bond structure
out there that I don't know about.
- --
John H. Kim
[email removed]
[email removed]