[Jackson96]

I Am doin an EEI on the effect of concentration on the voltage and current of a galvanic cell. so for it has shown that the higher the molarity the lower the voltage, why is this?

[thetada]

Can you describe the exact nature of the galvanic cell? Presumably it has two compartments linked by a salt bridge? In which case, is the concentration being increased in both compartments or just one? What are the electrodes made of?

[Jackson96]

The half cells contained zinc and copper, and we changed the concentration in both of them. we did an experiment at 0.01, 0.1 and 1 molar.

[thetada]

Do you mean that one electrode was zinc and the other was copper or that you had different solutions, one of which contained zinc ions and the other copper ions?

[Jackson96]

one half cell had copper electrode in copper nitrate and the other zinc electrode and zinc nitrate

[havdjufil]

The corelation between concentration and cell voltage is given by Nernst equation. Maybe there is an explanation why is this so on the pages discussing about this equation.

[Borek]

If you keep concentration ratio constant, voltage should not change (by much).  But you have still not shown any numbers that we can comment on. In fact we still don't know what was the procedure followed and how the experiment looked like.

[thetada]

I'm not certain about this but it did occur to me that it could involve the equation V = IR, where I is current and R is resistance in a circuit. Obviously with a higher concentration of ions, it's going to be possible for the electricity to bridge the electrodes more easily, unfortunately, not only am I uncertain as to whether that's the correct path to go down, I'm also uncertain as to what would happen further down the path. Shooting from the hip, I think that while the voltage is lower, the current is correspondingly higher. But, you could also argue that the higher concentration of circuit-bridging ions amounts to a reduction in resistance. There again, the galvanic cell is playing the role of the electricity provider in this circuit, and the value of R should describe the overall resistance on the other part of the circuit, ie the wires connecting the electrodes and the voltmeter. So my money's on low voltage but high current. I could be talking completely nonsense however.

[dazza95]

When we did this, we looked at increasing or decreasing temperature would have an effect on the voltage and current so these are just some suggestions on what we did find out about concentrations,

An electrolyte is a solution that is full of ions that help conduct electrical currents. The more concentrated the solution is, the more free ions it has.

Also look at the Nernst Equation
and Le Chatelier's principle about the change in concentration, (that should tell you heaps!)
And then look at the connection between these 2 equations.