Chemical Forums
Chemistry Forums for Students => Physical Chemistry Forum => Topic started by: Natla on November 06, 2008, 07:07:26 PM
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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.
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Supplying just temperature, pressure and amount is not enough to calculate the enthalpy of something.
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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.
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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).
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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.
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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.
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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.
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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!!!