Chemical Forums
Chemistry Forums for Students => High School Chemistry Forum => Topic started by: mizzle on October 16, 2009, 10:03:36 PM
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I have a question regarding the reaction of aqueous Barium Chloride and aqueous Sulfuric Acid...
I know that
BaCl2 (aq) + H2SO4 (aq) ---> BaSO4 (s) + 2HCl (g)
I was wanting to find the standard free energy change associated with this reaction...
but I cannot find a G value for BaCl2 at all...
I need to find if this reaction is spontaneous... I think that it is, because it forms a precipitate with no added
external influence... but I don't know for sure.
Help me?
Thanks!
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Any reaction that occurs at a temperature is definitely spontaneous at that temperature.
I didn't get you when you said G value for BaCl2. What does it signify?
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Hi Schrodinger :)
I meant gibbs free energy value, G :D
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There's no such thing as (https://www.chemicalforums.com/proxy.php?request=http%3A%2F%2Fwww.forkosh.dreamhost.com%2Fmimetex.cgi%3F%7B+%5CDelta+G+%7D&hash=6f092a20a2af142deff5196e84e7edef7e6d65c3) for a compound. You must calculate it for the entire reaction as such.
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Um,
Isn't there a standard G for every compound?
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There is a standard :delta: G of formation for every compound. The standard :delta: G of formation for BaCl2 is -858.6 kJ/mol.
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Hi Steak,
Where did you find that value?
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Hi again,
I really think the reaction between Barium Chloride and Sulfuric Acid is spontaneous... but if I use the value given to me
by Steak, I get that :delta:G is positive, which would indicate that the reaction is nonspontaneous...
Ugh... does anyone know this answer?
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That's the enthalpy of formation, :delta: H. my bad. it was on wikipedia
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To find the :delta: G standard for barium chloride....
:delta: G standard = :delta: H standard - T :delta: S standard
(Those values, except T, are here----> http://www.statemaster.com/encyclopedia/Barium-chloride)
Calculate room temperature in K and use that for the T variable. The :delta: G of formation value that you receive can be used to calculate the :delta: G of the reaction. I'm certain it's a spontaneous reaction.
here's a movie----> http://genchem.chem.wisc.edu/lab/CCA/MVHTM/H2SO/H2SOBACL.HTM
p.s. when calculating the :delta: G for the reaction, make sure you're doing....
(summation of :delta: G standard for products) - (summation of :delta: G standard for reactants)