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Topic: Hydrogen pressure  (Read 5721 times)

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Offline jokker

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Hydrogen pressure
« on: June 07, 2008, 12:12:38 PM »
I need it to compare.


So for example im getting 10 liter per min.
Hydrogen is at the normal pressure due surrounding air.
Its a gas at normal state.

For example i want to compress it to get it to liquid state.

I need to compare 2 states... I want to now how my 10l/min looks like in liquid state.


Some images













Offline jokker

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Re: Hydrogen pressure
« Reply #1 on: June 08, 2008, 06:07:33 AM »
Ok ... I guess it is complicated ...
But i found on internet that:
Hydrogen in liquid state is 788 more dense that is is at normal pressure for example 1 at.

Is there any formula i can use ?

So if im getting 10l per min then it will look in liquid state 0,0127 l per min = 0,761 l per h.  ???

Offline enahs

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Re: Hydrogen pressure
« Reply #2 on: June 08, 2008, 09:33:31 AM »
A quick google search for me showed up at it being 808 times more dense.

I am not really sure why you are surprised about that. Gases are not dense at all, in some fields of science that is the definition of gases.


Offline jokker

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Re: Hydrogen pressure
« Reply #3 on: June 08, 2008, 10:30:45 AM »
I knew that... as  i previously told that i need it to compare.

But what about hydrogen burning value. Is it higher that gasoline for example, and how much higher ?

Offline enahs

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Re: Hydrogen pressure
« Reply #4 on: June 08, 2008, 10:57:52 AM »
You tell me. Your Gen Chem book in the back should have tables of standard enthalpies. Write out the balanced equations for the two reactions and figure out the change in enthalpy. Which release more energy? You can look at it from two perspectives, which releases more energy per mole and per gram.



Offline jokker

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Re: Hydrogen pressure
« Reply #5 on: June 08, 2008, 02:21:28 PM »
Wow that sounds complicated  :o, But yea i guess i no how to do it.

They say that hydrogen is good fuel... and perfect energy carrier. Seems that it is better that battery coz it is used in hybrid cars.

Burning value is 4.1 - 75 % in air ... so i guess it is guide flammable. Or it tells that i can be used as air/oxygen  in fuel.

FFS it getting complicated.  :-\

I guess energy u get by burning it in car engine depends on engine itself. But it goes back to basics. For example if got higher pressures, temperatures in input then your getting better result in output.

But how much these enthalpies are linked to burning value ...

Offline enahs

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Re: Hydrogen pressure
« Reply #6 on: June 09, 2008, 08:28:19 PM »
Quote
But how much these enthalpies are linked to burning value ...

Again, you tell me.

When you use the values in the back of your book, what do you get for say, the enthalpy of combustion of octane? How does this compare to an experiment value (google for answer)?


It is actually much easier then you are making it out to be.


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