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Topic: HELP ME. I have NO Idea what my chem teach wants me to write!  (Read 405 times)

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Offline BushesBush

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HELP ME. I have NO Idea what my chem teach wants me to write!
« on: January 06, 2023, 01:32:16 AM »
Hi. So, my chemistry teacher has given me the task of explaining how a lab in which a galvanic cell was built works. However, he seems to have used another simpler variant to create the element. A variant that mimics electrolysis. Here is a picture of it.

The electrolyte in his experiments consists of acetic acid (CH₃COOH) and salt water (NaCl). The anode consists of Zinc while the cathode consists of Copper. There is no porous disc between the electrodes, nor is there a copper solution, zinc ion solution or a salt bridge.

And while I understand fairly well how Daniell's element works, I still don't understand how this works with regard to the reactions.

For example, how does the electrolyte used in this experiment interact with the electrodes? Does the electrolyte react in contact with the electrodes or only with the ions when oxidation has taken place at the anode?

Or the electrolyte never reacts with the zinc or the copper ions. The electrolyte just balances the charges without reacting with the ions (Zn2+).

For example, when salt dissolves in water, they create the chloride ion (Cl-). If this then reacts with the Anode, then I am thinking about whether the ion only gives up an electron (Cl  :rarrow: Cl + e-) or whether it is the zinc ions that react with the chloride ions (Zn2+ + 2Cl-  :rarrow: Zn + Cl2). Which of these is correct?

Along with this, the question arises as to how the reaction between the cathode and the cations takes place.
Is it as such that this happens (CH3COOH + H2O ⇄ CH3COO + H3O+) and then (2H3O+ + e- → 2H2O + H2)? Or do the cations react with negatively charged copper ions (CuX-) taking into account that the cathode received an abundance of electrons in the redox reaction?

Since then, I have not found any logical reaction that takes place between sodium ions (Na+) and electrons (e-) or copper ions (Cu-). The same applies to acetate ions (CH3COO–) and why they react with the anode (CH3COO + Zn2+ ?).

Another question mark. Is this thing still valid – Zn(s) | Zn2+(aq) || Cu2+(aq) | Cu(s) +. Is this still valid? Given that there is no boundary between the half-cells. Are there even half cells then and how would this cell diagram be drawn up? Especially considering that there isn't a copper and zinc ion solution either.

Last. Is it also as such that the anode is positive or negative and the same question for the cathode? They say that the anode (Zn) is the negative pole, but how is that true if it loses electrons? So that it gets a constant lack of electrons in relation to protons. At the same time, the cathode (Cu) also gets an abundance of electrons. Which should mean that it instead becomes the negative pole.

I will be super grateful if there is someone out there who wants to guide me in the right direction. Thank you for your help and time!

Offline Hunter2

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Re: HELP ME. I have NO Idea what my chem teach wants me to write!
« Reply #1 on: January 06, 2023, 02:12:04 AM »
Consider which Ions do you have in the electrolyte. Only these ones can do a reaction at the electrodes. The Anode is the place where oxidation takes place. The cathode got the reduction.
So what happen to the zinc. And does anything happen to copper if no copper is in solution?
« Last Edit: January 06, 2023, 03:15:03 AM by Hunter2 »

Offline Borek

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Re: HELP ME. I have NO Idea what my chem teach wants me to write!
« Reply #2 on: January 06, 2023, 03:13:41 AM »
Do you know the concept of the net ionic reaction? Some of the ions are inert, just spectators. In the context of this particular cell copper is inert, too, serves just as an electrode.

This is a variant of a lemon battery.
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