Calcium chloride reactions in a bag

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From: N. Gronert (ngronert@dcn.davis.ca.us)
Date: Sat Apr 03 2004 - 17:25:22 PST 

Message-Id: <p06002000bc9513ea7832@[168.150.192.74]>
Date: Sat, 3 Apr 2004 17:25:22 -0800
From: "N. Gronert" <ngronert@dcn.davis.ca.us>
Subject: Calcium chloride reactions in a bag

So what other reactions? If you mix baking soda and calcium chloride
in a bag, my students notice that often one side of the plastic bag
is warm and the other side is cold. The calcium chloride and water
are exothermic the book says so produce the heat, but what reaction
produces the cold?
Thanks, Nancy

>On Apr 2, 2004, at 4:23 PM, Treena Joi wrote:
>
>>From that, I did the chemistry in a bag thing and the teacher notes say
>>that calcium chloride and water evolve heat, yes, which is exothermic,
>>going on to say it is only a physical change ...
>>
>CaCl2 + H2O = CaOH + HCl
>
>among other reactions in that ziplok bag
>
>Burt Kessler
>
>
>
>"Science is nothing more than learning how to communicate with
>nature in such a manner that it will talk back."

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