From: Sally Seebode (sseebode@earthlink.net)
Date: Wed Jan 21 2004 - 15:58:48 PST
Message-ID: <007001c3e07a$8346e800$3105060a@smuhsd.k12.ca.us> From: "Sally Seebode" <sseebode@earthlink.net> Subject: coke can Date: Wed, 21 Jan 2004 15:58:48 -0800
HI Lou,
>In the procedure, the author said to open the can, pour out the
soda, replace it with water, then submerge the can into the lye
solution. My question is: Why pour out the soda? Why not just leave it
in there with the can still sealed? Were the inner liner to burst I
could see how the acid in the soda might partially neutralize the lye,
but other than that........
If you do not open the can, the pressure inside is much higher than outside,
so when you dissolved the aluminum, the plastic liner would break. You could
leave the soda inside, but most people want to drink the soda, not waste it
in an experiment.
>Can one of you chemistry types tell me what the chemical reaction is
between the NaOH and the aluminum can?
Don't know the exact reaction. Was told it was a complex ion of aluminum and
hydroxide.
> Is this experiment kind of like the acid dissolving the egg shell
away from the raw egg experiment, but at the other end of the pH scale?
I guess.The result shows the liner of each.
>Any practical applications for this new found knowledge?
I use it to talk show why the soda, with a pH between 2 - 3, does not react
with the metal can (as our properties of acids would predict).
>My daughter and I plan to try this with different brands of soda, and
some cans having the paint removed and others not, maybe even a can or
two that is only half way stripped of its paint.
>Anything else I should know?
The liner is fragile and breaks easily. Be careful not to dent the can
before the experiment as this makes the inside liner weaker and more likely
to break.
Hope this helps.
sally
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