Can Hydrogen be made from air and water?

[sr241]

Is forming ammonium nitrate and hydrogen from air and water is possible.

N2+3H2O > NH4NO3 +H2

Is this reaction exothermic?

Ammonium nitrate has enthalpy of formation of -365.1

 

[Deathcrush]

no, it is not possible, ammonium nitrate is ussually produced mixing nitric acid and ammonium hidroxide,

HNO3+NH4OH--->NH4NO3+H2O

you want to blow something up huh?

 

[sr241]

Actually I was looking for sustainable way to produce hydrogen. Ammonium nitrate is widely used as fertilizer, so there will be a cycle hydrogen to water again to hydrogen. and a nitrogen cycle: nitrogen to ammonium nitrate to nitrogen by plants>animals>secretion>bacteria

Is water is the stablest form of hydrogen?

 

[Astronuc]

The OH bond is pretty stable, and there is certainly a lot of water on the Earth's surface. I believe M(OH)_x, where M is a metal element and x is some integer, are quite stable, but not sure which one is most.

 

[Deathcrush]

also water is very stable because of hydrogen bonds , if you want to produce Hydrogen gas just add an inorganic acid to some metal, like HCl and Al for instance, there are many other ways, like electrolysis on water

 

[Dickfore]

Ammonium nitrate has enthalpy of formation of -365.1

where did you come up with that number?

 

[sr241]

i found it from internet (wikipedia)
production of ammonium nitrate from ammonia and nitric acid is exothermic . but my question is it exothermic from water and nitrogen?

 

[Deathcrush]

well, I already got a warning for answering just like that, so why don't you calculate it yourself? just look for an enthalpy table and use Hess's Law, draw some lewis's structures to know which bonds are broken and which are formed

 

[Dickfore]

No. The enthalpy of formation is a function of state and is calculated as if the compound is formed directly from its constituents. If you know the enthalpy of formation of the reactants (which are also compounds in your case) and of the products, then the enthalpy of the reaction is:

$$\Delta_{r} H = \sum{H_{f}(\mathrm{products})} - \sum{H_{f}(\mathrm{reactants})}$$

IF this turns out to be negative, the reaction is exoergic. If it is positive, it is endoergic. However, this does not give you the whole information about the kinetics of the reaction, as there might be a huge potential barrier for this reaction to start (activation energy).

 

[sr241]

2 N2(0)+4 H2(0)+3 02(0) > 2 NH4NO3 [(-365.1)*2]
since enthalpy is negative the first reaction is exothermic

N2(0)+3 H2O[(-241.8 )*3] > NH4NO3(-365.1) +H2(0)

so enthalpy of second reaction will be -365.1 - (-241.8 *3)= +360.3, thus the second reaction is endothermic right

values in brackets () are enthalpy of formation.

So producing hydrogen from second reaction is not viable since it consumes more energy 1.7 times more to produce one mole of hydrogen than directly from water, right?