# Thread: How to find the stored electicity in a material???

1. How do I find what the amount of stored electricity is in a material? I particularly would like to know how much stored electricity there is in a pound of Aluminum if it was to be broken down chemically.

2.

3. This doesn't really make much sense - there is no "electricity" stored in a pound of aluminium. Do you mean "chemical potential energy" ?

4. please forgive my ignorance. If aluminum is broken down chemically with sodium hydroxide, how much electricity is produced per pound of Aluminum?

I see Aluminum as a battery. If the aluminum oxide is scrubbed off with sodium hydroxide and the raw Aluminum is allowed to contact water, the result of the reaction is to create Aluminum oxide and hydrogen and a release of electrons. Is this correct? If so, is there a way to figure out the potential amount of electricity that could be released from a pound of Aluminum that is submerged in a vessel filled with a sodium hydroxide solution?

5. I think this question is better suited to the Chemistry section. Moved.

6. There are no electrons released in this reaction:
2 Al + 6 H2O -> 2 Al(OH)3 + 3 H2

The reagents and the products are electrically neutral.

7. Originally Posted by Strange
There are no electrons released in this reaction:
2 Al + 6 H2O -> 2 Al(OH)3 + 3 H2

The reagents and the products are electrically neutral.
Er, steady on. Al is oxidised to Al ³⁺, releasing 3 electrons, while water gains them (i.e. is reduced), releasing hydrogen and producing hydroxide.

An electrochemical cell simply separates the two halves of processes such as this, in such a way that electricity is forced to flow through wires in order to complete the reaction. I'm sure someone whose electrochemistry is less rusty than mine would be able to look up the electrode potentials for the half cells and work out what voltage this reaction would generate if set up as an electrochemical cell.

8. Originally Posted by exchemist
Originally Posted by Strange
There are no electrons released in this reaction:
2 Al + 6 H2O -> 2 Al(OH)3 + 3 H2

The reagents and the products are electrically neutral.
Er, steady on. Al is oxidised to Al ³⁺, releasing 3 electrons, while water gains them (i.e. is reduced), releasing hydrogen and producing hydroxide.
True. There is no net gain or loss of electrons, though.

An electrochemical cell simply separates the two halves of processes such as this, in such a way that electricity is forced to flow through wires in order to complete the reaction.
Indeed. But that didn't seem to be what the OP was asking.
Aluminium battery

9. Originally Posted by Strange
Originally Posted by exchemist
Originally Posted by Strange
There are no electrons released in this reaction:
2 Al + 6 H2O -> 2 Al(OH)3 + 3 H2

The reagents and the products are electrically neutral.
Er, steady on. Al is oxidised to Al ³⁺, releasing 3 electrons, while water gains them (i.e. is reduced), releasing hydrogen and producing hydroxide.
True. There is no net gain or loss of electrons, though.

An electrochemical cell simply separates the two halves of processes such as this, in such a way that electricity is forced to flow through wires in order to complete the reaction.
Indeed. But taht didn't seem to be what the OP was asking.
Aluminium
Ah. What I had in mind was the poster's subsequent clarification of the question: "is there a way to figure out the potential amount of electricity that could be released from a pound of Aluminum that is submerged in a vessel filled with a sodium hydroxide solution?"

10. Ah yes. I missed that somehow.

11. 1.21 gigawatts.

12. Originally Posted by klickitat
please forgive my ignorance. If aluminum is broken down chemically with sodium hydroxide, how much electricity is produced per pound of Aluminum?

I see Aluminum as a battery. If the aluminum oxide is scrubbed off with sodium hydroxide and the raw Aluminum is allowed to contact water, the result of the reaction is to create Aluminum oxide and hydrogen and a release of electrons. Is this correct? If so, is there a way to figure out the potential amount of electricity that could be released from a pound of Aluminum that is submerged in a vessel filled with a sodium hydroxide solution?
One bit of this I can do however is work out the charge transferred if 1lb of Al is oxidised to Al +3. Call it 500g of Al. Atomic weight of Al is 27g so 500g is 18.5mol of Al, which will release 3 x 18.5 = 55mol of electrons, also known as 55 Faradays of charge.

1 Faraday ~ 10 ^5 coulombs.

So, our 1lb of Al will generate around 5.5 million coulombs of electric charge if it is all oxidised to Al 3+, or around 1,500 amp-hrs, at a potential of the order of a couple of volts or so.

13. Thank you exchemist. That is exactly what I was looking for.

14. PHDemon, Thanks for the link. That has been my morning read and will most likely go into lunch as well.

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