AnonyDD123
Badges: 10
Rep:
?
#1
Report Thread starter 1 month ago
#1
Hi! im a bit unsure of what the functions of the different components are in an electrochemical cell. so firstly, is the electrolyte there to increase the concentration of ions in solution? Why is a high resistance voltmeter used?
0
reply
charco
Badges: 17
Rep:
?
#2
Report 1 month ago
#2
(Original post by AnonyDD123)
Hi! im a bit unsure of what the functions of the different components are in an electrochemical cell. so firstly, is the electrolyte there to increase the concentration of ions in solution? Why is a high resistance voltmeter used?
The high resistance voltmeter is to ensure that no-current passes - that way the concentrations in the half-cells remain constant and the cell potential can be measured accurately.
1
reply
AnonyDD123
Badges: 10
Rep:
?
#3
Report Thread starter 1 month ago
#3
(Original post by charco)
The high resistance voltmeter is to ensure that no-current passes - that way the concentrations in the half-cells remain constant and the cell potential can be measured accurately.
charco but if no current passes, doesnt that mean that electrons are not allowed to flow? so electrons dont actually move from the anode to the cathode when connected by a voltmeter?
0
reply
charco
Badges: 17
Rep:
?
#4
Report 1 month ago
#4
(Original post by AnonyDD123)
charco but if no current passes, doesnt that mean that electrons are not allowed to flow? so electrons dont actually move from the anode to the cathode when connected by a voltmeter?
Correct.

Voltage or EMF(electromotive force) is just a force, it does not require a flow of electrons. It is the push/pull caused by the potential difference between the anode and the cathode.
0
reply
AnonyDD123
Badges: 10
Rep:
?
#5
Report Thread starter 1 month ago
#5
(Original post by charco)
Correct.

Voltage or EMF(electromotive force) is just a force, it does not require a flow of electrons. It is the push/pull caused by the potential difference between the anode and the cathode.
excellent thank you so much charco. and also, the electrode being dipped in an electrolyte with the same ions, is that because when the electrons move to the cathode, there needs to be a source of ions to gain electrons to form the solid metal on the electrode?
0
reply
charco
Badges: 17
Rep:
?
#6
Report 1 month ago
#6
(Original post by AnonyDD123)
excellent thank you so much charco. and also, the electrode being dipped in an electrolyte with the same ions, is that because when the electrons move to the cathode, there needs to be a source of ions to gain electrons to form the solid metal on the electrode?
The electrode potential at the electrodes is caused by the equilibrium between the atoms on the electrodes and the ions in solution.

For the Zn(s)|Zn2+(aq) electrode, the equilibrium is:

Zn2+(aq) + 2e <==> Zn(s)

The electrode potential is measures relative to the standard hydrogen electrode as -0.76V.

This means that the equilibrium, as written, tends more to the LHS than the standard hydrogen electrode equilibrium:

2H+(aq) + 2e <==> H2(g)

For a Cu2+(aq) |Cu(s) electrode, the electrode potential is +0.34V.
So the equilibrium:

Cu2+(aq) + 2e <==> Cu(s) tends more to the RHS than the standard hydrogen electrode.

If the copper half-cell is connected to the zinc half-cell, then the zinc half cell will try to move to the LHS and the copper half-cell will try to move to the RHS.

It is this difference in potential (potential difference) that causes the voltage registered in the high resistance voltmeter. The zinc half-cell is pushing electrons and the copper half-cell is pulling electrons.
0
reply
X

Quick Reply

Attached files
Write a reply...
Reply
new posts
Back
to top
Latest
My Feed

See more of what you like on
The Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

Personalise

Do you think receiving Teacher Assessed Grades will impact your future?

I’m worried it will negatively impact me getting into university/college (7)
46.67%
I’m worried that I’m not academically prepared for the next stage in my educational journey (0)
0%
I’m worried it will impact my future career (1)
6.67%
I’m worried that my grades will be seen as ‘lesser’ because I didn’t take exams (3)
20%
I don’t think that receiving these grades will impact my future (1)
6.67%
I think that receiving these grades will affect me in another way (let us know in the discussion!) (3)
20%

Watched Threads

View All