Electrolysis Question

[deledio]

does increasing the amps increase the reaction rate?
i don't think voltage does, but not sure about the amps

[mark_alec]

Higher current --> more electrons travelling per unit time --> faster reaction.

[deledio]

thanks

[pinchies]

by increasing the voltage can't you get different chemicals reacting depending on concentration?
Also, from physics, if we assume the resistance of a electrochemical cell remains constant, won't increasing the voltage also increase the current, hence make the reaction go faster?

Sorry if this is considered thread hijacking (?), I thought it was relevant.

[Pandemonium]

irrelevent.

they don't assume physics knowledge in chemistry.

[Mao]

increasing voltage can allow different chemicals to react, but I assume that the strongest oxidant/reductant pair will always react, and these have the smallest E^o difference [with the exception of chlorine, which reacts in preference of water in higher concentration, and i believe that also changes its E^o value].

and as for the other question, I'd think that constant resistance cannot be assumed. the energy required for the reaction to occur is is the E^o difference, and it may very well be that electrons from the supply can have higher energy, this energy would be converted to kinetic energy in the reaction, i.e. the solutions/electrode heats up slightly. Hence the more energetic the electrons are [voltage], the more heat is released [current].

Another way to combat this simply is to change the power output of the supply, though I really don't think it's of any relevance to the study design =]

[pinchies]

Thanks Mao, that makes it much clearer.   

We talked a bit about the chlorine situation during a prac, but I didn't quite understand it. I don't think it is not on the study design, we only need to know at std. cond.

[Mao]

actually, the opposite. They may ask you questions on non-standard conditions but only about chlorine [when it is concentrated, it reacts preferentially to water].