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Topic: Reactions that don't occur at room temp  (Read 4184 times)

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Offline Kuahji

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Reactions that don't occur at room temp
« on: May 02, 2008, 12:58:52 AM »
Which reaction does not readily occur at room temperature?

2 HCl + Zn(OH)2 -> ZnCl2 + 2 H2O

Cu2+ (aq) + 4 NH3 -> Cu(NH3)4 2+ (aq)

NH3 + HCl -> NH4Cl

2 HCl -> H2 + Cl2

Given only the given information, how can I tell which one doesn't occur at room temperature?  The only thing I could really think of, is perhaps entropy.  NH3 + HCl -> NH4Cl does appear to go from 2 molecules to one but so does Cu2+ (aq) + 4 NH3 -> Cu(NH3)4 2+ (aq), here though it is just (aq).  Am I at least headed in the right direction?  Do I even need to know the different states or more information?

Offline DrCMS

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Re: Reactions that don't occur at room temp
« Reply #1 on: May 02, 2008, 05:27:07 AM »
What do 3 of the reactions have in common?
Under what conditions do that type of reaction occur?

Offline AWK

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Re: Reactions that don't occur at room temp
« Reply #2 on: May 02, 2008, 06:43:28 AM »
Which reaction can be called a thermal decomposition?
AWK

Offline Kuahji

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Re: Reactions that don't occur at room temp
« Reply #3 on: May 02, 2008, 06:14:06 PM »
Which reaction can be called a thermal decomposition?

Didn't think about it like that, we've been talking so much about entropy of late, totally forgot about thermal decomposition.   :)

But that does make sense & would really only leave one reaction left, 2 HCl -> H2 + Cl2, so that is what I'm going with. 

Thank you both for responding. 

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