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Topic: Enthalpy Calcultor/Software?  (Read 10755 times)

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Offline Natla

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Enthalpy Calcultor/Software?
« on: November 06, 2008, 07:07:26 PM »
Hi,

Im after a calculator or software that can tell me the enthalpy of a gas.
I want something where I can enter the variables and have it tell me the enthalpy. The variables are mass (in moles), temperature and pressure.

So far I have seen ones that only use temperature and mass but not pressure.

Does anyone know where I can find one to use/download?

Even ones that must be paid for are fine.

Thanks for any help in advance.

Offline enahs

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Re: Enthalpy Calcultor/Software?
« Reply #1 on: November 06, 2008, 10:42:22 PM »
Supplying just temperature, pressure and amount is not enough to calculate the enthalpy of something.

Offline Natla

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Re: Enthalpy Calcultor/Software?
« Reply #2 on: November 07, 2008, 05:25:35 AM »
Oh really. What else needs to be know to calculate enthalpy?

Degrees of freedom?

Im after software. Please just point me in the right direction.

Thanks.

Offline enahs

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Re: Enthalpy Calcultor/Software?
« Reply #3 on: November 07, 2008, 08:40:05 AM »
Are you talking about calculating the change in enthalphy ( :delta:) for an ideal gas?
Show me an example calculation.

Enthalpy is a state function, and is dependent on the identity of the gas and the change in temperature.

Either way, it is very easy to program into your calculator or use a spread sheet.
Search the internet for spread sheet help or read the help file of your spread sheet (Excel is Microsoft Office suite, Calc in OpenOffie suite).

Offline Natla

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Re: Enthalpy Calcultor/Software?
« Reply #4 on: November 10, 2008, 10:55:22 AM »
Hi,

OK, so for a real gas (air), where its pressure and temperature are at a high level then changes to zero.
This is an example calculation.

How would this be calculated in the manner you described?

Cheers.

Offline Hunt

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Re: Enthalpy Calcultor/Software?
« Reply #5 on: November 15, 2008, 06:03:31 AM »
You can use classical thermodynamics to calculate the enthalpy of a gas relative to a certain state.

$$ H_{(T,p)} = H_{(T_o , p_o)} + \int_{T_o}^T C_p dT + \int_{p_o}^p Vdp - \int_{p_o}^{p} T ( \frac{dV}{dT}_p ) dp /$$

Depending on the equation of state used and the type of the gas involved, the integrals are evaluated.

Offline enahs

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Re: Enthalpy Calcultor/Software?
« Reply #6 on: November 15, 2008, 10:44:26 AM »
So, again, you are trying to calculate the change in enthalpy!

It is pretty simple.
Say I have the linear function
y=mx + b

In cells in Excel I can label a section for the m, the x and the b.
In the Y cell I type "="
then click on the m cell, then type "*" and click on the x cell, and then type "+" and click on the b cell.
Then, whatever I put into those cells will be evaluated and give me the correct answer for Y.

http://www.saskschools.ca/~ehs/HeiseIntra/excel.html
Look at the tutorials for unit 1.

Again though Hunt, as I asked, the Enthalpy is dependent on the identity of the gas.


Offline semper erectus

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Re: Enthalpy Calcultor/Software?
« Reply #7 on: November 26, 2008, 10:14:58 PM »
just visit this sites...

www.3d2f.com/tags/enthalpy/calculator/gas/ - 18k
www.brothersoft.com/steam-calculator-69579.html - 15k
www.measurementdb.com/index.php?name=Web_Links&req=viewlinkdetails&lid=1325 - 37k -
www.filesrepository.com/software/enthalpy.html - 14k
torrents.com
rapidshare.com
rapidlibrary.com


and check out the net, there's a lot of sites in there. these are the common site that i've been using to download a software.
hope these would help you...
good luck!!!

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