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Offline sorincosofret

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Daniel cell and the problems rised in physics - part III


In already presented materials posted on the naked scientist or my site, the connection between two wires and the formation and functioning of electrochemical cells was detailed. Now is time to learn the ,,high tech” personalities of modern physics, how a cell can be discharged. It seems that a simple schoolboy knows this even before to have the age necessary to primary school. It is more difficult to teach people who have already a Ph D  such simple things. 

Experimental part
A ,,formal Daniel cell” is formed using a Zn electrode immersed in a ZnSO4 1M solution and on the other hand a Cu electrode immersed in a CuSO4 solution. The solutions are connected with a salt bridge formed by CaCl2 in agar agar as presented in posted materials. CaCl2 was preferred instead of KCl due to the simplicity of Ca ions detection in an analytical way.
Before cell formation the mass of Cu and Zn electrodes was measured with an analytical balance.
Once the cell formed, the difference of potential is measured and this is 1,070 V.
Further, in order to speed up the processes from electrodes, the Zn and Cu electrodes are connected by a metallic wire (short circuit) as in figure.




In order to have a element of comparison a normal alkaline battery of 1,5 V bought from the market is connected in a similar way (the plus and minus pole with a metallic conductor).
After 1 day, the metallic wire is disconnected and the difference of potential is again measured. The value found for the ,,Daniel cell”  is the same 1,070 (±0.01) V, like before short circuit.
The difference of potential in case of alkaline pile from supermarket is
0±0.01 V.
Looking at pile, the Zn electrode appears without any consume, at Cu electrode no deposition.
The electrodes are again connected in short circuit and after 3 days, the procedure of measuring the difference of potential repeated. Strange enough, the same value 1,070 (±0.01) V was counted.
It is very strange how a ,,normal” Daniel cell resist so long, compared with a commercial battery.
Again the electrodes are connected in short circuit and after one week the procedure of difference of potential measuring is repeated.
And …. Bingo… the value of electrochemical cell is the same, precisely 1,070 (±0.01) V. The experiment was made few years ago and I stopped the experiment after about one month, with the difference of potential the same like at beginning of experiment (1,070 ±0.01 V). At the end of experiment the Zn electrode has the same mass, the same metallic lustre (appearance) like before the experiment. The Copper electrode has an increased mass with 0.01 g due to the extended contact with CuSO4 solution. There is no migration of ionic species from bridge to solution after 7 days of cell working.
A repetition of experiment was made last week, and soon, I will post some picture here. The results are the same (only the potential difference is 1,075±0.01 V), and this difference of potential remain constant even the cell is already in short circuit from more then 5 days.
With this cell (anyone who is able to prepare simple solution and knows how two wires can be connected, can repeat the experiment), it seems that perpetual mobile was already discovered by physics (but is not aware of it), and all problems of absence of energy are resolved.
But this is only imagination. The same imagination (and even more) is manifested by all scientists (dead or alive) who are treating the Daniel Cell without trying to build one and to see how is working and if it’s working.


Our ,,genies of physics” presents difficulties in understanding some simple concepts so I  avoid to present here even the actual interpretation of the Daniel cell. Who will make the experiment will observe the difference between what has learned in any school and what is measured.
The entire discussion will be presented in the book (as usual).




« Last Edit: 14/08/2008 08:34:21 by sorincosofret »


 

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Re: Daniel cell and the problems rised in physics- part III
« Reply #1 on: 10/08/2008 21:04:34 »
"It is very strange how a ,,normal” Daniel cell resist so long, compared with a commercial battery."
No it isn't strange, the commercial battery has a much lower internal resistance so it generates a lot more current. In doing so it uses up the electrode materials more rapidly. Your battery works so badly it can't even flatten itself. Try measuring the short circuit current from your cell. A typical commercial celll will deliver a few amps (briefly).

Incidentally, Don't short circuit batteries. It's generally a bad idea, particularly with rechargeables.

"it seems that perpetual mobile was already discovered by physics (but is not aware of it), and all problems of absence of energy are resolved."
 It may seem like that to you, but not to those of us who understand these things.

What will be the point of presenting all this in a book?
It's mainly rubbish.
 

lyner

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Re: Daniel cell and the problems rised in physics- part III
« Reply #2 on: 11/08/2008 08:36:00 »
It's one thing to write a book and another thing for people to buy it!
 

Offline sorincosofret

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Re: Daniel cell and the problems rised in physics- part III
« Reply #3 on: 11/08/2008 13:47:31 »
As I promised, the pictures of perpetual mobile of actual physics are attached to the posted material.


Daniel cell upwards



Daniel cell edgewise



Daniel cell value after 8 days of working in shortcircuit


For those who want to have some fun and to understand a little bit the further estimations the following link is useful: http://www.giocomania.org/pagine/18121/pagina.asp

Let’s estimate the time of life for a Daniel cell in short circuit mode and the consequences of a pile working.

The resistance of salt bridge is about 16 kΩ and the resistance of solution about 4 KΩ.
Let’s exaggerate and consider that internal resistance of battery is 50 KΩ.
In this condition considering the external circuit of resistance zero the short-circuit current is:

I =U/(R+r)= 1,07/50 000=21 micro A.

By comparison with the lemon battery presented in the reminded link, where such device has 500 microamperes in short circuit, my battery works bad and slower with only 21 microamperes in shortcut.

A little bit deeper into actual physic:
I = Q/t = ne/t
Where n = number of charge in our case electrons
e the charge of electron
t – time of working in short-circuit

The actual Daniel battery is working in short circuit already from 8 days which means 691200 s.

The number of electrons which has already passed by external conductor is:

n = I*t/e=6,912/1,6 * 10 exp (-19) =0,9072 *10 exp(20) electrons

These numbers of electrons are coming from the Zn dissolution reaction

Zn (s) → Zn2+  + 2e-

Which means a number of 0,4536*10 exp(20) atoms of Zn are already in solution.
For this number of Zn  cation a double number of hydroxyls ions must come from salt bridge.
Let’s calculate the decreasing of Zn mass electrode ( I suppose the Avogadro number is still known by elites) :
Mass of Zn passed in solution is :
0,4536*10 exp(20)*65,37/(6,023*10exp(23)) =4.92 mg

Let’s calculate the size of hydroxyl quantity present in the cell

For the salt bridge 5 ml of 0,1 M NaOH were diluted to 75 ml agar agar solution.
After that the tube was filled with 20 ml of this solution.
The quantity of NaOH in 5 ml solution is: 20 *10 exp (-3) g
In the tube there is a quantity is 5 *10 exp (-3) g
From this mass the mass of hydroxyl ions are 5*17/40 = 2.125 mg


The stoechiometry of reaction:
Zn2+ + 2HO-= Zn(OH)2

65,37 mg     2* 17 mg
4.92………      y

y = 2,55 mg

So in order to neutralise the 4,92 mg of Zn2+ there are necessary 2,55 mg OH-.

But the total quantity of hydroxyl available in the entire bridge is only 2,125 mg.
Considering that all this quantity is flowing into Zn compartment, there will remain still an excess of Zn cations already moving into solution and searching for anions able to maintain the neutrality of solution. Of course in the Cu compartment there is excess of anions moving into solution and searching for cations able to maintain the neutrality.
The cell is still working at full potential after 8 days, and this means there is a transfer of cations and anions from cathodic space to anodic space through salt bridge.
Can actual science confirm this?
In the same time if all hydroxyl is passed into solution the Zn compartment should have an alkaline pH.
This is not confirmed by direct measurements - both compartment are at pH about 5, in acid region and not alkaline.
How is possible for formed Zn(OH)2 to have a week acid pH?
Further analysis must regard the formation of Zn(OH)2 precipitate.
Of course in order to make this analysis a new known chemistry concept must be used named Product of solubility. I doubt that in the high field of theoretical physics this concept is used so I will tray to explain it like for schoolboys. When the concentration of a certain substance in a solution overpasses a certain limit (solubility product), a precipitate will appear.
The product of solubility of Zn(OH)2 is KSP = 3 *10 exp (-17), in chemical terms, this means it is necessary a very, very  small quantity of the substance to precipitate.
I leave for high intelligence as homework to verify if in the up presented condition Zn(OH)2 form a precipitate.
Because it is difficult for a physicist to understand a little bit chemistry I provide even some help (where other physicists asks how can be converted a number from a scale to another , of course without asking what is the meaning of that numbers):
http://www.physicsforums.com/showthread.php?t=104676
The circulation of hydroxyl and sodium ion through the agar agar gel is only a hypothesis without any real fundament. When the experiment will be stopped, the bridge will be analyzed. If NaOH does not pass into solution, it should be confirmed its persistence into gel.
The up presented calculus was made considering a very low rate of current flowing and exaggerating the internal resistance of the cell.
In reality, a workable pile (based on an exothermic reaction) with electrodes in short-circuit mode should cease its activity in maximum few days. When a cell is working in short circuit more then one week, something is wrong in the experimental or theoretical approach. In our case, both actual experimental and theoretical premises are completely pure imagination
The problem with the Daniel cell having a salt bridge in its constitution regards the absence of a chemical reaction. In this case only a static (contact) difference of potential is measured which lasts forever. The subject is detailed in the book, due to its relative importance from theoretical point of view.
If someone mix Zn, ZnSO4 and KCl (CaCl2, NaOH, etc) no reaction take place.
The same if Cu and CuSO4 and KCl are mixed.
The original Daniel cell, invented in 1836 by John Frederic Daniell, does not have a salt bridge, even the ingredients are quite the same.
From simple elementary school manuals to the high scientific treatise, the Daniel cell is presented with a salt bridge ….but this cell has never worked and will never work.

From week to week an update of information’s for this experimental cell (maintained in short circuit) will be provided.


« Last Edit: 11/08/2008 14:10:22 by sorincosofret »
 

Offline davetest

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Re: Daniel cell and the problems rised in physics- part III
« Reply #4 on: 11/08/2008 15:12:44 »
Quote
It is very strange how a ,,normal” Daniel cell resist so long, compared with a commercial battery.
No it is not strange at all, a 'normal battery' has a very low internal resistance so that some of the energy that flows through it is transferred to the bulb or ipod it is powering, plus it will use very thin pieces of metal to save weight

A Daniel cell will have a huge internal resistance, so very little current will be flowing - hence if you short circuit it you will have to wait ages for it to go flat, have you tried measuring the current passing through your two cells?
 

Offline sorincosofret

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Re: Daniel cell and the problems rised in physics- part III
« Reply #5 on: 11/08/2008 15:25:00 »
Dave,
Huge what does it mean ?
I've measured it and is about 20 KΩ.
Of course related to a market battery with a Resistance of few ohms is huge...
Can you verify the up presented demonstration where the cell reaction and energy producing is detailed. As you see the internal resistance of the formed cell is doubled in the calculus as in reality. This means a real time for discharging half then calculated one.
Even so, a cell can't resist in shortcut mode more then few days. It's a matter of experimental facts. For a chemical reaction to occur and to produce energy, there is a speed of this chemical reaction.
Besides this time (quite long apparently) for a cell verification there are other methods able to help us to identify how a cell is working properly.
Precipitates can be observed, change of basic-acid character of a medium, isotopic techniques etc.
These are detailed in about 5 posts at chemistry and physics forum.

In the same time the discussion about a real Daniel cell ,,resistance " is absurd. Daniel pile was used for more then half a century for telecommunications. If the internal Resistance of this cell was so high and the external current so low, none should use it.
The true problem is the real Daniell cell does not have a salt bridge.

« Last Edit: 11/08/2008 15:37:22 by sorincosofret »
 

lyner

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Re: Daniel cell and the problems rised in physics- part III
« Reply #6 on: 11/08/2008 16:58:13 »
If you are determined to claim that this cell is an inexhaustible supply of energy, I suggest you measure the masses of the reagents at the beginning and at the end of a test, during which you measure the charge passed and the PD across the cell. To prove your theory, you would have to show that the metered energy (QV) as more than that which you would expect from the change in reagent levels. Do you actually know how to work it out, using conventional Chemistry? You may not like it but, if it works out right, there is no need for your alternative explanation.
 

Offline sorincosofret

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Re: Daniel cell and the problems rised in physics- part III
« Reply #7 on: 11/08/2008 19:25:56 »
For those who are interested in a more realistic description of Daniell cell:
http://www.answers.com/topic/daniel-cell
I extract from this page:
The Daniell cell was a great improvement over and is somewhat safer than the voltaic cell used in the early days of battery development.
What improvement bring this cell (instead of Voltaic cell) if his resistance is so huge that all theoretical current is consumed by its internal resistance.

A variant of Daniell cell called gravity cell described on the same webpage was renamed as the Exchange Telegraph Cell because it was used by the Exchange Telegraph Company..
How it was possible to use such cell for electrical signal transmission when its generated current in shortcircuit mode is few microamperes. When there is also a external resistance the current is even lower. Probably two century ago, they worked with miles of battery connected in order to arrive at a reasonable current or there was another civilisation on the Earth having a high technology.

In reality both Daniell cell and gravity cell have nothing to do with the modern representation of Daniel cell with a salt bridge.
In the first cases described on the www.answer.com, there is a countable current produced by this battery, because there is a chemical reaction behind the entire phenomena.
In the modern representation of Daniell cell (found in every book of physics and chemistry), there is no reaction between components. Practically this Daniel cell is like a toy car for the children. Has the same apparency, but the engine to work properly is missing.
 

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Re: Daniel cell and the problems rised in physics- part III
« Reply #8 on: 11/08/2008 19:43:04 »
Sorin, once again you seem to be ignoring reality.
Zinc can react perfectly well with water, hydroxide or acid so the limited amount of hydroxide in the bridge has no importance whatsoever.

A properly designed Daniel cell has a reasonably low resistance. Your's isn't and doesn't.

By your own reckoning the loss of zinc is only a few milligrams- unless you weigh the electrodes before and after the experiment you wouldn't be able to see that small a loss. I take it that the reason you haven't weighed them is because a real weight loss would spoil the mystery. After all  "perpetual motion until the zinc runs out" isn't very impressive.

And this statement"The true problem is the real Daniell cell does not have a salt bridge." is nonsense
Here's a fairly early patent which details an improvement in the Daniel cell.
http://www.google.com/patents?id=GjBjAAAAEBAJ&pg=PA1&dq=daniell+cell&source=gbs_selected_pages&cad=0_1#PPA1,M1
The diagram clearly shows a porous pot which is the salt bridge in this case.
Similarly, the wiki article says "The Daniell cell proper consists of a central zinc anode dipping into a porous earthenware pot containing zinc sulfate solution. The porous pot is, in turn, immersed in a solution of copper sulfate contained in a copper can, which acts as the cell's cathode. The use of a porous barrier prevents the copper ions in the copper sulfate solution from reaching the zinc anode and undergoing reduction. This would render the cell ineffective by bringing the battery to equilibrium without driving a current."

Why are you still talking nonsense about these things?

 

Offline davetest

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Re: Daniel cell and the problems rised in physics- part III
« Reply #9 on: 11/08/2008 20:09:52 »
Huge what does it mean ?
I've measured it and is about 20 KΩ.
Of course related to a market battery with a Resistance of few ohms is huge...
Yes 20 kΩ is what I would call a huge internal resistance for a battery. If you connected a conventional battery to a 20kΩ resistor it would take months to discharge... just like your cell.
 

Offline sorincosofret

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Re: Daniel cell and the problems rised in physics- part III
« Reply #10 on: 11/08/2008 21:03:24 »
Dave,
Please make again the mathematical treatment with a resistance of 20 KΩ instead of exaggetared value of 50 kΩ used by me , and you will see that the salt bridge is exhausted after 4 days. How can the cell work without it?
Secondary there is enough time (months) to wait for the cell discharge. It does not ask nothing for eating. I fill in with small volume of water from time to time in order to maintain the same volume decreased by evaporation.
But i think there is a better solution ...What do you think about a Daniel cell with a salt bridge but all internal resistance of less then 1 KΩ?
I'm working of it....


 
« Last Edit: 11/08/2008 21:12:28 by sorincosofret »
 

Offline davetest

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Re: Daniel cell and the problems rised in physics- part III
« Reply #11 on: 11/08/2008 21:56:52 »
At this point you will probably get sulphate ions moving up through the bridge in one direction and Zn2+ ions moving in the other direction in order to cancel out the charge difference. In order to balance out the charges this must happen anyway.
 

Offline sorincosofret

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Re: Daniel cell and the problems rised in physics- part III
« Reply #12 on: 12/08/2008 05:46:18 »
Dave,
You have got the idea.
But this is not all.
Imagine my perplexity when I made for the first time this experimental cell and the theory and my practice told me that the cell must be discharged after a period of time .... but the cell refused to do that...
Imagine my perplexity when the theory told me that the salt bridge is exhausted .. but the cells potential was the same.
Imagine my perplexity when the simple lows of chemistry are violated - hydroxyl ions moving without pH modification,precipitates does not appear even there is a concentration which overpass the product of solubility, etc.
Imagine now my perplexity when instead of having comments on the experimental or theoretical part presented in the posted material, the stupid comments are related to books sold or to some Chinese characters transliterated in Latin alphabet (PD, QV etc).

From chemistry point of view is very easy with the actual techniques to identify a moving species. The problem is ..... there are no species moving. The cell with a salt bridge does not work because the principal reaction must be:
Zn +CuSO4  →  ZnSO4 +Cu.
There are no condition for this reaction.
When a metal is dipped into its salt solution there is no a sort of this type of reaction:
Zn reversible arrow  Zn2++ 2e-
(this can be tested with isotopic techniques).
The contact between ZnSO4 and CuSO4 with the salt bridge does not produce any chemical reaction too.
In this condition only a static potential is measured which lasts forever. It is similar to  the contact potential between two metals.
More then that, actual techniques permit a 4 mg measurement with a good precision or as I mentioned the experiment can wait till the decreasing is higher.
I work properly with sample having 30 micrograms (0.03 mg) and there is no great deal to weigh in such small quantity. 

« Last Edit: 12/08/2008 05:59:06 by sorincosofret »
 

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Re: Daniel cell and the problems rised in physics- part III
« Reply #13 on: 12/08/2008 07:00:34 »
"you will see that the salt bridge is exhausted after 4 days. "
No, as I said, it won't.
*Imagine my perplexity when I made for the first time this experimental cell and the theory and my practice told me that the cell must be discharged after a period of time .... but the cell refused to do that..."
 You already explained that. The Zn electrode should only have lost 5 mg.
"Imagine my perplexity when the theory told me that the salt bridge is exhausted .. but the cells potential was the same."
Also already explained.
"Imagine my perplexity when the simple lows of chemistry are violated "
 They are not.
"Imagine now my perplexity when instead of having comments on the experimental or theoretical part presented in the posted material, the stupid comments are related to books sold "
You have steadfastly ignored the comments on the "science", is it any wonder that we question the book's utility?







 

Offline Alan McDougall

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Re: Daniel cell and the problems rised in physics- part III
« Reply #14 on: 12/08/2008 13:16:32 »
There is no free lunch, like it or not you must pay for it somewhere down the line
 

Offline sorincosofret

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Re: Daniel cell and the problems rised in physics- part III
« Reply #15 on: 12/08/2008 13:42:49 »
Sorry Alan,

I'm not a good English speaker in order to understand the subtility of your proverb or sentence. Please reformulate in order to understand your thought.
 

Offline rosy

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Re: Daniel cell and the problems rised in physics- part III
« Reply #16 on: 12/08/2008 13:59:34 »
I think probably Alan is refering to the assumption (on which most of modern science is ultimately based) that in terms of energy you can't get something for nothing.. or in other words that if you think you've created a perpetual motion machine, the overwhelming likelihood is always that you're wrong.

(Correct me if I'm misinterpretting you, Alan)
 

lyner

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Re: Daniel cell and the problems rised in physics- part III
« Reply #17 on: 12/08/2008 14:52:29 »
I did wonder about suggesting a modification to the title of this thread which could involve exchanging 'modern physics' with 'the originator's ideas'.
 

Offline sorincosofret

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Re: Daniel cell and the problems rised in physics- part III
« Reply #18 on: 12/08/2008 15:19:23 »
Rosy,
You have right.... and if this is Allan interpretation, I'm agree with both.
In a salt bridge Daniell cell, there is no reaction so a contact potential remain stable and for a indefinite time.
Of course, there is a misinterpretation regarding the high value resistance of such cell. In the second text regarding Daniel cell there is a case when the electric current is travelling through such salt bridge. After one day the Zn and Cu electrode (as presented in photo) suffer visible changes. In fact the Zn electrode disappear completely.
From practice it is known that wet cells are able to have a larger amperage than a dry cell, and of course Daniell cell is a wet one.
In a salt bridge cell, there is no energy consume, so there is no perpetual mobile in reality. Is like the difference of potential between two metals (here there are more contact potential with a more complex interpretation). Once you connect both metals, the difference become 0.If they are disconnected, the difference change to the same value like before connection.
From where come this contact potential energy? None will give you a reasonable answer, but in any case it does not represent a source of infinite energy.

Another affair is the real Danill cell - without a salt bridge (which for actual physicists), become a low internal resistance cell and can deliver an reasonable electric current.


 

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Re: Daniel cell and the problems rised in physics- part III
« Reply #19 on: 12/08/2008 18:47:48 »
Sorin.
There is a salt bridge in a normal Daniel cell.

Why do you keep ignoring this simple fact?
 

lyner

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Re: Daniel cell and the problems rised in physics- part III
« Reply #20 on: 12/08/2008 23:15:46 »
Sorin.
There is a salt bridge in a normal Daniel cell.

Why do you keep ignoring this simple fact?

In a gravity cell or a porous pot cell, is there a salt bridge?
It strikes me that one reason for the high internal resistance of the salt bridge cell is the long path through the salt bridge and the small cross section.
The gravity cell has a large interface area and a very short 'length' of interface so could be expected to have a low internal R. The porous pot might be expected to have a slightly higher R than this, because of the geometry of the construction. Is that the case in practice?
It strikes me that the name 'Daniel Cell' covers a wide range of applications and some of this thread may be at odds as a consequence.
But there ain't any perpetual motion, of course!
« Last Edit: 12/08/2008 23:19:11 by sophiecentaur »
 

Offline sorincosofret

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Re: Daniel cell and the problems rised in physics- part III
« Reply #21 on: 13/08/2008 06:49:11 »
The entire discussion seems to go in a philosophical or no meaning direction. The purpose of the post is a experimental one. For those who didn't get the idea (or have difficulty in understanding the concepts presented here), I invite to make himself the folowing very simple experiments:
a piece of copper and Zn connected to a Voltmeter are inserted into a CuSO4 solution.
a piece of Cu and Zn connected to a Voltmeter are inserted in a H2SO4 solution.
Both phenomena (oxidation and reduction took place at the same electrode - more precisely Zn electrode - and the Voltameter indicate in thesame time the difference of potential expected for the cell.
It is not necessary to have a Ph D diploma to see where the Cu is deposited or where the hydrogen is released.
If instead of voltmeter (which is know to have a great resistance) the electrodes are short circuited, the whole situation is changed.. as presented in second post related to the Daniel cell.
After that, please search in any book of chemistry or physics, where is written that both oxidation and reduction take place at the same electrode and a potential difference appear.
Please indicate to me (and to other readers) ... and after that anyone can understand what is the meaning of ,,absurdity of modern physics " from the title
Please indicate me how the electrons in the same electrode (because both half reaction are in the same point) jump and cry.... and a difference of potential appear...
There is a absurdity of approaching of the whole electric and chemical phenomena  and the physics and conservative physicist must be aware that electricity is not the field of relativity where is very difficult to test what\s happened at the light speed.
I have no intention for the moment to enter into more details, but it will be the time for all ...
« Last Edit: 13/08/2008 07:02:04 by sorincosofret »
 

blakestyger

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Re: Daniel cell and the problems rised in physics- part III
« Reply #22 on: 13/08/2008 09:01:12 »
The entire discussion seems to go in a philosophical or no meaning direction.

Philosophical discussions are NOT synonymous with 'no meaning' discussions.
 

Offline sorincosofret

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Re: Daniel cell and the problems rised in physics- part III
« Reply #23 on: 13/08/2008 15:08:55 »
Blakestyger,
Agree with you in principle, but not in this particular case.
A philosophical and extended discussion means to loose the purpose of the experiment and its new ideas. There was a tactic in the dead socialism regime... true is good when is hidden on a unknown page of a mountain of papers.
I pointed out a simple experiment and its consequences, I made even a mathematical treatment and I'm interested to be corrected if the experiment or calculus are faulty.
 

Offline rosy

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Re: Daniel cell and the problems rised in physics- part III
« Reply #24 on: 13/08/2008 15:24:04 »
Right. So. Some maths (for as they say, a day in the library is worth a week in the lab).

For the copper half-equation occuring in the copper side of the cell:

Cu2++ 2 e -reversible arrowCu      V = +0.340

And for zinc:

Zn2++ 2 e -reversible arrowZn      V = -0.76   (values taken from wikipedia)

This gives a calculated value for the cell potential under standard conditions of 1.1 V, which is pretty much what is observed (tho' note that 1 M Cu2SO4 is not molar in Cu2+).

So far so good.

Taking the solutions as in your diagram above, the amount of copper sulfate in the solution gives you 0.4 mol of Cu2+, which as I'm going to assume a 1 g Zn electrode on the zinc side gives us plenty of solution to play with... 1 g of Zn is only 0.015 mol.

Using the limiting reagent (Zn) from here on in...

6.02 x 1023 atoms (or whatever) in a mol.

So 1.2 x 1024 electrons lost to oxidise 1 mol of Zn.
1.8 x 1022 to oxidise 1 g of Zn (atomic weight of zinc is about 65).

6.24 x 1018 electrons in 1 C (coulomb) of charge, so it takes 2.9 x 103 C of charge flowing through the circuit to oxidise all the 1 g Zn electrode.

If the resistance is 20 KΩ (which is quoted above somewhere as the internal resistance of the system) since V = 1.1 V as above and V = IR, current is about 5.5 x 10-5 A or equivalently 5.5 x 10-5 C s-1 so it'll take 5.2 x 107 s or 1.4 x 106 hours or 610 days to discharge (which is to say to run out of zinc) even if it's only driving current through a short circuit!

If you stopped the experiment after one month, I'd expect to see a decrease in the mass of the zinc electrode of about 50 mg and a corresponding increase in the mass of the copper of about the same (their molecular masses are pretty similar). If you're using very impure zinc you might see some residue under the electrode but if it was nice and clean to start with you won't. The copper will be plated with clean copper.

The salt bridge will not be "exhausted" because the ions diffuse through it and will be replaced from either end as they do.

Seriously, if you want to overturn modern physics you can't just argue from incredulity ("I don't understand it, therefore it must be wrong"). No one is going to reproduce your "miraculous" experiments, given that we can work out from current theory what we expect to see happen and you're showing us a perfectly respectable set of results showing us exactly that. Pity your grasp of theory is so far out, you seem to be making a perfectly respectable stab at recording your observations.
 

The Naked Scientists Forum

Re: Daniel cell and the problems rised in physics- part III
« Reply #24 on: 13/08/2008 15:24:04 »

 

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