# what happens to the energy?

sonhouse
Posers and Puzzles 21 Nov '06 20:54
1. sonhouse
Fast and Curious
21 Nov '06 20:54
You have a rechargable battery, fully charged. Then you put it in some solvent that can dissolve the entire battery to molecules. Where does the energy in the original charge go? Like you charge it up to 10 amp hours, a 2 volt cell would have the energy of 2 volts at 10 amps for one hour so that would be 20 watt hours of energy invested in the battery, which is then dissolved. What happened to that 20 watt hours of energy?
2. AThousandYoung
All My Soldiers...
21 Nov '06 21:03
Originally posted by sonhouse
You have a rechargable battery, fully charged. Then you put it in some solvent that can dissolve the entire battery to molecules. Where does the energy in the original charge go? Like you charge it up to 10 amp hours, a 2 volt cell would have the energy of 2 volts at 10 amps for one hour so that would be 20 watt hours of energy invested in the battery, which is then dissolved. What happened to that 20 watt hours of energy?
I think it would end up heating the solution.
3. uzless
The So Fist
21 Nov '06 21:22
Originally posted by AThousandYoung
I think it would end up heating the solution.
yup, energy converted to heat
4. sonhouse
Fast and Curious
21 Nov '06 21:332 edits
Originally posted by uzless
yup, energy converted to heat
So theoretically an experiment could be done to quantify the effect?
1500 watts of heat for one hour is about 5000 btu/hrs of heat, so
20 watt hours in our example would be about 60 btu's so in that unit system it would heat up 6 pints about 10 degrees F more than if you dissolved a discharged battery?
Has anyone ever heard of just such an experiment? It's similar to the idea of a compressed spring dissolved in acid, where does the energy of compression go?
5. uzless
The So Fist
21 Nov '06 21:541 edit
Originally posted by sonhouse
So theoretically an experiment could be done to quantify the effect?
1500 watts of heat for one hour is about 5000 btu/hrs of heat, so
20 watt hours in our example would be about 60 btu's so in that unit system it would heat up 6 pints about 10 degrees F more than if you dissolved a discharged battery?
Has anyone ever heard of just such an experiment? It to the idea of a compressed spring dissolved in acid, where does the energy of compression go?
picture two springs in acid. one spring compressed, the other not compressed.

The not compressed spring will dissolve as usual.

The compressed spring's molecules are compressed with the compression force acting upon them. The acid must overcome this compressive force in order to dissolve the spring. Energy (in the form of heat) is released during this dissolving process at a rate equal to the amount of potential energy contained in the compressed spring.
6. sonhouse
Fast and Curious
21 Nov '06 22:26
Originally posted by uzless
picture two springs in acid. one spring compressed, the other not compressed.

The not compressed spring will dissolve as usual.

The compressed spring's molecules are compressed with the compression force acting upon them. The acid must overcome this compressive force in order to dissolve the spring. Energy (in the form of heat) is released during thi ...[text shortened]... g process at a rate equal to the amount of potential energy contained in the compressed spring.
Yes, I get that part. What I want to know if anyone ever heard of an experiment to quantify the effect.
7. AThousandYoung
All My Soldiers...
21 Nov '06 23:13
Originally posted by sonhouse
Yes, I get that part. What I want to know if anyone ever heard of an experiment to quantify the effect.
I don't know. You'd need to take into account any energy released or absorbed due to the solvation reaction as well.
8. sonhouse
Fast and Curious
22 Nov '06 15:191 edit
Originally posted by AThousandYoung
I don't know. You'd need to take into account any energy released or absorbed due to the solvation reaction as well.
Yep, all the extraneous heat loads would have to be accounted for and subtracted from the final temp. readings to get the spring energy. I would have thought that would have been done somewhere. It seems like a simple high school level experiment. Two solutions, one with a spring unwound, put in what, nitric acid?, then measure the temp, then do it again under identical parameters with the exception of now the spring is coiled up tight. That leads to some difficulties, maybe it would have to be held together with a non-reactive cable tie or something, so the tiedown would not add extraneous data to be accounted for.
You would have to be able to calculate the potential energy of the coiled spring and convert that to calories or BTU to make a prediction of the expected rise in temp.
9. PBE6
Bananarama
22 Nov '06 19:29
Originally posted by sonhouse
Yes, I get that part. What I want to know if anyone ever heard of an experiment to quantify the effect.
Found a reference to one on this website:

http://www.science.ca/askascientist/viewquestion.php?qID=761
10. uzless
The So Fist
22 Nov '06 19:471 edit
Originally posted by PBE6
Found a reference to one on this website:

http://www.science.ca/askascientist/viewquestion.php?qID=761
Finally, I get an answer correct! Must be the new type of beer I'm drinking

(As is rather obvious, I'm not much of a mathematician, more of a theoretical conceptualist....which proves to be quite useless most of the time ðŸ˜ž )