Measuring of electrode potential.

[chewchun]

In set-up with two half-cells and a voltmeter, the potential difference is measured using the voltmeter.
But voltmeter has high resistance,which i know is still able to measure potential difference,but wouldn't it prevent electrons from flowing
What i meant was,the use of voltmeter creates a 'open circuit' which prevents electron flow and hence reaction in the two half cell will not take place?
But my teacher says that reaction takes place in both half cell,which meant that there is electron transfer and redox??
Does this have to do with some physics regarding voltmeter??

 

[Borek]

Voltmeter closes the circuit, it doesn't leave the circuit open. What voltmeter does it measures the current flowing through a known resistance, then it displays the result as potential (V=RI).

Actually it is not a chemistry question, but physics question - how does the voltmeter work and what happens in the circuit with a voltmeter (doesn't matter if it is a battery powered circuit or some other kind).

 

[chewchun]

Voltmeter closes the circuit, it doesn't leave the circuit open. What voltmeter does it measures the current flowing through a known resistance, then it displays the result as potential (V=RI).

Actually it is not a chemistry question, but physics question - how does the voltmeter work and what happens in the circuit with a voltmeter (doesn't matter if it is a battery powered circuit or some other kind).

So the high resistance of voltmeter must play a role.what if there is no voltmeter,for instance just a strip wire...is experiment the same?
Btw wouldn't the high resistance prevent current from flowing or something like that??

 

[Borek]

Please read how voltmeter works and how it measures the potential difference, your questions are directly answered by the theory behind it. Most likely any general physics book will do.

You can't understand potential measurement without good understanding what a potential difference is and how it is related to the charge, and what happens when you close the circuit - that's all physics.

 

[LudusRex]

The use of a voltmeter does not prevent electrons from flowing in a half-cell setup. The voltmeter is designed to have a high resistance, which means it will not draw a significant amount of current from the system. This allows for accurate measurement of the potential difference between the two half-cells without interfering with the electron transfer and redox reactions taking place. The voltmeter acts as a "bridge" between the two half-cells, allowing for the measurement of the potential difference without affecting the overall reaction. This is due to the principles of electrical circuits and the fact that the voltmeter is connected in parallel to the half-cells, not in series, which would interrupt the flow of electrons. Therefore, the use of a voltmeter does not hinder the reactions taking place in the half-cells.