H Veeder <hveeder...@gmail.com> wrote:

> Ok so you can design a calorimeter to detect this particular endothermic
>> reaction, however, if you don't know a-priori what type of endothermic
>> reaction or what energy source is involved a "standard" calorimeter might
>> fail to detect it.
>> Harry
> ‚ÄčAnother potential problem is that a calorimeter designed to detect an
> exothermic reaction might prevent an unknown endothermic reaction which is
> a prerequisite for the exothermic reaction. ‚Äč

A calorimeter cannot be designed for exothermic or endothermic reactions.
If it can measure an increase in heat, it can measure a decrease with the
same accuracy and precision. When a reaction produces heat and then stops
producing it, the calorimeter always shows that decline. You always see the
power fluctuating up and down; the calorimeter always measures in both
directions equally well. With an endothermic reaction the decline goes
below the starting point. That's the only difference. The calorimeter does
not care about that.

If the cell was storing up energy, you would see it for sure. Scott Little
showed a beautiful example of this once. He put a rechargeable battery into
a calorimeter and charged it up. There was a deficit comparing electricity
to the rising temperature. Then he discharged the battery through a
resister in the cell. All the lost energy came back. The balance was close
to zero.

- Jed

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