[MT64]

Hi, I'm just starting the year in AP Chemistry and I'm having trouble understanding what exactly is happening in these reactions:

NH₃ (aq) + HC₂H₃O₂ (aq) + H₂O (l) 
NH₃ (aq) + HCl (aq) + H₂O (l) 
NH₃ (aq) + BaCl₂ (aq) + H₂O (l) 
NH₃ (aq) + CuSO₄ (aq) + H₂O (l) 

I'm trying to understand by googling answers but some of them conflict with each other or don't contain phases. I know that NH₃ becomes NH₄ and that a base forms hydroxide ion in the product, but why is it that NH₃ (aq) + HCl (aq) + H₂O (l) forms NH₄Cl (or does it)? Where did the O go? Can anyone break it down so that I can understand what's happening?

Thanks in advance

[Borek]

No need for H₂O(l) in all these equations - it doesn't take part in neither of the reactions (it just serves as a solvent). Remove water, try to balance again.

[MT64]

No need for H₂O(l) in all these equations - it doesn't take part in neither of the reactions (it just serves as a solvent). Remove water, try to balance again.

Okay I think I got it, bases take protons and acids donate them:

NH₃ (aq) + HC₂H₃O₂ (aq) NH₄C₂H₃O₂ (aq)
NH₃ (aq) + HCl (aq)  NH₄Cl (aq)
NH₃ (aq) + BaCl₂ (aq) + H₂O (l) 
NH₃ (aq) + CuSO₄ (aq) + H₂O (l) 

but what about the last two? How does aqueous ammonia react with aqueous salts? I'm looking at http://answers.yahoo.com/question/index?qid=20111026174211AAQ3NLb and hydroxide ions are created but how and why do they do what they do?

[Borek]

http://www.youtube.com/watch?v=IDDrf8vKtcU&hd=1

I don't think anything would happen with BaCl₂. While Ba(OH)₂ is weakly soluble, ammonia is not a base strong enough to precipitate the hydroxide, and in general alkaline earth metals don't get complexed as easily as the transition metals.