Re: Determining CO2 Concentrations in Natural Waters

[David Sanchez <barbax2@yahoo.com>]

"I'm 
not
picking sides to cause trouble..............really I'm

not.............!!!!!"

If I had a nickel for all the times you said that on
the Apisto list I'd be a rich man Jacobs. But it's ok
I know your true colors.

Good night Meat Tits

Dave :)






--- Mike Jacobs <mjacobs2@tampabay.rr.com> wrote:
> .......................Youngker's in my
> canoe.................that was the
> damnest explanation I've ever seen.  I've read it 4
> times and will have to
> do it 2-3 more times and talk to our chemistry
> teacher at school.  I'm not
> picking sides to cause trouble..............really
> I'm not.............!!!!!
> And all I wanted to do was grow some
> foxtail.............just add another
> fluorescent tube Mike..........heh, heh,
> heh.........wow!  Somewhere in
> there I should be able to use differentiation or
> integration to grow that
> foxtail.................remember in there about
> trying to divide by
> zero...................I followed that.....;-) ;-)
> ;-).....you know the
> definition of a "black
> hole"??????..................................it's
> where God tried to divide by
> zero......................
> 
> ...............I think we all ought to go to Java
> moss................;-)
> ;-) ;-)
> 
> ....hey Big John........I didn't see anything about
> "blue goop" in there.
> did you!!
> 
> Mike
> 
> Mike Jacobs
> Center for Advanced Technologies
> High School Math Instructor
> St. Pete, Fl.
> ----- Original Message -----
> From: "David A. Youngker" <nestor10@mindspring.com>
> To: "Apistogramma Mailing List" <apisto@listbox.com>
> Sent: Monday, January 28, 2002 6:42 PM
> Subject: Determining CO2 Concentrations in Natural
> Waters
> 
> 
> > > From: David Sanchez
> > > Sent: Monday, January 28, 2002 3:56 PM
> >
> > > I think you just don!'t understand the
> relationship
> > > between pH and carbonic acid...
> >
> > David -
> >
> > I'm afraid that it is you that has confused a few
> issues. Let's see if we
> > can walk through this in an academic manner and
> arrive at some sort of
> > "consensus", shall we?
> >
> > > KH and pH both determine the level of CO2 in a
> > > body of water. This comes from a basic
> > > understanding of the pH equation.
> >
> > There is no "pH equation", per se - only the
> _definition_ of pH, which is
> an
> > inverse log of the actual *count* of hydrogen ions
> in a solution. It's a
> log
> > scale because we're dealing with _huge_ numbers
> here, and the numbers we
> > _do_ use are in effect the *exponent* of the
> value.
> >
> > The level of free hydrogen in the solution is
> totally dependent upon what
> > the various solutes _release_ into the solvent.
> Since the most commonly
> > found buffer in natural systems, from stream  beds
> to bloodstreams, is the
> > bicarbonate ion, we usually have to look no
> further than the dissociation
> > constant of that ion to see how many hydrogen ions
> it will provide.
> >
> > The formula you're probably thinking of is the
> bicarbonate equilibrium
> > described by the commonly-referenced
> >
> > H2CO3 <=> H+ + HCO3-
> >
> > which shows the products and reactants in relation
> to the equilibrium
> point.
> > The actual point itself, determined through about
> 150 years' of empirical
> > data collected by analytical chemists, is
> described as a ratio of products
> > to reactants in a comparison of their creation
> rates. When there are as
> many
> > hydrogen ions and bicarbonate ions being produced
> as there are being
> > consumed, we have achieved "equilibrium" around
> the value
> >
> > ([H+][HCO3-])/ [H2CO3] = 4.3 x 10-7
> >
> > Therefore, to determine the pH of the solution
> involved, we solve this for
> > the hydrogen concentration as
> >
> > [H+] = ([H2CO3][4.3 x 10-7]) / [HCO3-]
> >
> > which ties the hydrogen content to the ratio of
> carbonic acid- to-
> > bicarbonate ions.
> >
> > This gives us a starting point for the rest of the
> conversation.
> >
> > > This whole buffer solution system is so
> misunderstood
> > > by many hobbyists in my opinion. Why will pH
> fluctuate,
> > > just because we have a KH of 0 do we assume the
> pH will
> > > simply bounce all over the place?
> >
> > If you're using bicarbonates as the predominant
> buffer, then that puts KH,
> > carbonate hardness, or alkalinity (or whatever the
> popular hobby term is
> > presently) right square in the denominator of the
> above ratio. What
> happens
> > when you try to divide by zero? (By the way, since
> the charts on Erik's
> site
> > is based on the Hendersen-Hasselbach equilibrium
> you'll find that same
> > "divide by zero" problem as the reason the charts
> break down at the
> > extremes. A zero in the denominator also
> represents reaction
> *completion*.)
> >
> > > The relationship of KH to pH, is not if we have
> 0 KH
> > > then we no longer have a !'buffer!( this is a
> incorrect
> > > way of looking at this...
> >
> > It is _not_ the incorrect way of looking at this -
> it _is_ the *only* way
> to
> > look at this. The "KH" is THE primary natural
> buffer within the equation.
> So
> > if you have no buffering agent, you can have no
> buffering. There _are_
> other
> > buffers at work in our Apisto tanks down at the
> ranges we work on, and
> their
> > related to the humics most of us introduce through
> peat/tannin filtering
> >
> > > A high KH will help maintain a Higher pH and
> vice
> > > versa a low KH (for example a 0 KH)will help
> maintain
> > > a lower pH...
> >
> > A buffering agent is one that absorbs or lessens a
> stressor applied to the
> > system. In this case, the stressor is the
> concentration of hydrogen, which
> > in our tanks is usually on the rise thanks to the
> processes of
> > nitrification.
> >
> > Buffers are established with a combination of an
> acid and its salt or a
> base
> > and its salt. In this case, the carbonic is the
> acid and the bicarbonates
> > are its base salt. The difference between the two
> is the added hydrogen,
> > which turns HCO3- into H2CO3. It is the "change of
> state" in capturing or
> > releasing the hydrogen that provides the
> buffering. If there is an influx
> of
> > hydrogen through, say, acids, then the product
> side of the equation
> relieves
> > the added pressure by combining the hydrogen with
> a bicarbonate to produce
> > carbonic. If we destroy the hydrogen through, say,
> the 
=== message truncated ===


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