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Re: Books/ammonia

> From: Romano <romano at pathway1_pathcom.com>
> Subject: Re: Books
> Karen Randall has asked the question, "Can you believe the books?" and I
> would be interested to hear fron any chemist who could possibly comment on
> her statement that:

	O.K., I'll comment.

> "Ammonia and ammonium exist in equilibrium",

	That's right.

> in response to my statement
> that, "Ammonia is called ammonium in water with a PH less than 7."

	That's wrong.

	The point is that there is a dynamic equilibrium between the two.
The two species change back and forth _very_ quickly.  The more alkaline
the solution, the more ammonia there is, and the more acidic, the more
ammonium there is.  It isn't just a matter of the name.  At a pH of 9.25
or thereabouts, there are equal amounts of the two. At pH 8.25 there is ten
times as much NH4+ as NH3.  At 7.25 there is one hundred times as much
NH4+ as NH3.  Any given molecule switches back and forth very rapidly
indeed, but the numbers of each species at any instant are as described 

	When it comes to aquarium books, the chemistry explanations
vary from poor to just plain wrong, at least in those I have seen.

Paul Sears        Ottawa, Canada