Electrochem help- Calling Physics Buffs (1 Viewer)

[norez]

I came across a practice question that i don't quite understand. It reads:

"The volume of electrolyte in the half cell affects the current, but does not significantly alter the voltage produced by the cell. Explain. (2)"

I understand that the voltage produced is only changed by changing the types of metals used, not their amount. (I think...) So what exactly is current, and why is that affected by the changing volume of the electrolyte? Please help.

_______

Also, "Give reasons for the difference between the experimental voltage value and the theoretical voltage value."

I have:
- Not standard lab conditions of 25 C and 100kPa
- Not having exactly 1 mol electrolyte solutions (how does that impact it?)
- Different surface areas of electrodes
- Corrosion or oxidation on the surface of the electrode
- Using a dodgy salt bridge (we use folded filter paper soaked in KNO3)
- Corrosion on surface of wires/ dodgy wires.

Are these valid? Anything else?

Thanks!!

 

[ohexploitable]

Current is the rate of flow of charge, an increase in volume of electrolyte results an increase of the number of ions that can undergo oxidation (I think, not too sure about this one). Voltage is electrical potential difference, it is the energy per unit charge. Think about it this way,

Case 1: 100 cars travel down a road, each with 4 passengers.
Case 2: 10 cars travel down a road, each with 4 passengers.

In this situation, the cars are the current and the passengers are the voltage, case 1 clearly has more current but both still have the same voltage.

 

[jamesfirst]

Or maybe you can think of potential energy as this way:

Think of currents (flow of charge) flowing in a conductor. They will have potential energy (stored energy) and as they move (flow) their potential energy will convert into kinetic energy (because work is being done, if you don't do physics, meh.), because it moves basically.

Now if there is a change in potential energy from 1 place to another (1 part of the conductor to another part), that is the potential difference (difference in potential energy since it has converted into kinetic energy)