[NewCandle] crystallization weight change transients

[Keith Nagel]

Fair enough on the hot air thing.

As concerns the endothermic crystallization, wouldn't
it be the case that salts that are exothermic on
dissolution would be endothermic on crystallization?
The devil we know, comes to mind, although that would
be rather bothersome to work with. How about ordinary
table salt?

Here's another question. The reference Colin provided
describes a solution of 3 parts by weight of the salt
to one part water. How close are you now to this ratio?

K.

-----Original Message-----
From: newcandle-bounces at ipdiscover.com
[mailto:newcandle-bounces at ipdiscover.com]On Behalf Of Nick Reiter
Sent: Wednesday, September 27, 2006 3:15 PM
To: New energy for the new world.
Subject: Re: [NewCandle] crystallization weight change transients


Yo,

When I did the first couple of runs, I used the ground
glass stopper that came with the flask.  However, I
worried a bit about whether that would hold the
internal flask pressure from slightly expanded warmed
air.  If its seal was not good enough to prevent
displacement, then I wondered how much of a hot air
balloon would I have with the flask proper.

So I went to a viton rubber stopper that makes a
compressive champagne cork type seal.  This I have
used for both the crystal and the NaOH warmed runs. 
Additionally, it was the same flask!  I had to decant
out the hypo-S and clean the flask before doing the
NaOH or hotplate baselines... I only have one of them!
 It's a very nice little flask though.  100ml
volumetrics are kewwwt.

So unless I am missing something, check and check on
the seal notion.

BTW - ran a hypo-P this afternoon, with more jazz. 
Not quite as good - only about 1.5 mg weight decrease.
But much more to come.

Here is a thing, though.  When the hypo-P takes off,
its like a million spined sea urchin - literally an
expanding hemispherical front of tiny needles.  The
hypo-S grows rapidly into blades and monoclinic
blocks.  To me, the latter seems like it has more
intrinsic order, but I don't quite know how to define
that in more specific thermodynamic terms.

Any input from the peanut gallery as to readily
soluble salts that would be endothermic in
crystallization would be hugely appreciated. 

I'm saving the exotics for later.  Thorium nitrate
seems pretty soluble.

N 

--- Keith Nagel <NewCandleAdmin at ipdiscover.com> wrote:

> OK, here's a possible method to control for this
> bubble problem. As we can't really get rid of the
> hot air, how about sealing both the control and
> active flask? Now if you match the temperature
> profiles,
> you'll have pretty much elimated all possible
> artifact.
> 
> K.
> 
> 
> -----Original Message-----
> From: newcandle-bounces at ipdiscover.com
> [mailto:newcandle-bounces at ipdiscover.com]On Behalf
> Of Nick Reiter
> Sent: Wednesday, September 27, 2006 1:58 PM
> To: New energy for the new world.
> Subject: Re: [NewCandle] crystallization weight
> change transients
> 
> 


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