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Topic: Calorimetry Literature Values  (Read 4585 times)

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Offline Cyberconvict

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Calorimetry Literature Values
« on: March 27, 2006, 07:23:03 PM »
I'm doing a calorimetry lab that is supposed to calculate the ?H values between an acid and a metal. When I'm figuring the heat flow of the reaction, I'm using q = mCp?T assuming that m is the mass of the metal and the volume in mL of acid used, Cp I'm assuming is 4.18J/C, and ?T I'm getting from the thermometer. If my calorimeter constant is 56 J/C I need to multiply that by ?T and add that value into q=mCp?T to get the total heat flow, correct?

The lab also asks for literature values for ?H of each reaction. I'm assuming I can use enthalpies of formations and Hess's Law to figure that, but to do that I need a larger chart of ?Hf values than my book can offer.

I'm going to give an example to make sure I have the correct thought process.
2HCl(aq) + Fe(s) --> FeCl2(aq) + H2(g)
?H = (?Hf(FeCl2(aq) + ?Hf(H2(g)) - (2?Hf(HCl(aq)+?Hf(Fe(s))
The H2(g) and Fe(s) would both equal 0 and the HCl(aq) value is -167.2kJ/mol. If I could get the value of FeCl2(aq) I could calculate the ?H in this method, couldn't I?

Thank you in advance.

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