Anode/Cathode, which one is positive and negative? (1 Viewer)

[aussiechick007]

the anode is always the positive electrode and the cathode is always the negative electrode as far as i know.... in chem its like that in galvanic cells... and in physics in cathode ray tubes and that the anode is still positive and the cathode is still negative... always...

ive no idea what yous are all on about here!!

 

[kooltrainer]

the anode is always the positive electrode and the cathode is always the negative electrode as far as i know.... in chem its like that in galvanic cells... and in physics in cathode ray tubes and that the anode is still positive and the cathode is still negative... always...

ive no idea what yous are all on about here!!

lol... anode is always negative! and cathode is always positive in chemistry..
for physics, my teacher specifically told us that cathode rays work in the exact opposite with the negative one being cathode and positive one anode..
and since current goes (-) -------> (+).. it is therefore called cathode rays..

 

[vds700]

lol... anode is always negative! and cathode is always positive in chemistry..
for physics, my teacher specifically told us that cathode rays work in the exact opposite with the negative one being cathode and positive one anode..
and since current goes (-) -------> (+).. it is therefore called cathode rays..

for galvanic cells, the anode is -ve and cathode +ve, but in electrolytic cells, its the other way round to make things even more confusing for you lol.

 

[karnage]

Since im doing ideas to implementation in physics now, i brought that up with my physics teacher and said that in chemistry the anode is -ve and the cathode is +ve. But my chemistry teacher said she never mentioned -ve or +ve for this reason as it adds to confusion, and i just realised that she never ever said it or was it in my workbook. So i must of just assumed it.

 

[qmaz]

in physics, we look at whats happening on the outside, ie

in chemistry, we look at the reactions on a chemical level, internally.

i think its that way around....for some reason, thats the reason lol

 

[aussiechick007]

oh my i should stop reading this thread!

the anode is positive people! the cathode is negative! theres no other way for it!

see in galvanic cells, oxidation happens at the anode, meaning electrons are given off, giving it a positive nature! and then those electrons travel along the wire to the cathode, where reduction occurs, and because electrons are arriving at it, it gives the cathode a negative nature!

that has always worked for me...

oh and in physics, the cathode is obviously negative...

 

[dumarab]

When a current is being generated the anode is negative and the cathode is positive.

When current is needed it's the opposite

 

[cheney31]

the anode is always the place where oxidation is occuring (ANOX)
cathode is always the place where reduction is occuring

just remember that and everything works out.
in chemistry:
for galvanic cell: electron from anode to cathode hence anode is -'ve and cathode is +'ve
for electrolytic cell: take CuCl2 solution for example. the side which Cl gas is produced (oxidised) is the anode (definition), and from experiment it is connected to the positive terminal. hence the anode is positive (as the electrons being "pulled out" by the +'ve terminal through external circuit to negative. see conq chem p348)


im not sure for phy .. i just accept.. the way i remember is that its cathode ray so cathode is firing the electron. since electron is -'ve then the cathode must be -'ve to create repulsion..

 

[undalay]

When a current is being generated the anode is negative and the cathode is positive.

When current is needed it's the opposite

Complete truth.
Ignore all other posts.

 

[hon1hon2hon3]

In chemistry anode is the one that gives out electron , and cathod is the half cell that reciews it.

There for anode is negative because of the present of electron. thus cathod is positive.

But simiply, in physics , by convention . . . they first thought that electron moves from positive to negative .

So in physics way of thought, electron moves from anode to cathod , thus anode is the positive , and thus cathod is the negative.

Just sharing my thoughts, Peace ~

 

[Darrow]

Remember,
With chemistry you are working with whats happening inside the cell..
That is anode -ve cathode +ve
Whilst physics deals with what happens outside the cell ,
Thus electrons come from the cathode and flow to the anode (Conventional current)

Anyone know why we havent changed conventional current to what actually happens?
Isn't science flogging a dead horse here?

 

[hon1hon2hon3]

what i heard from the teacher is that , there will be no difference if we swap positive and negative now , since we know it , its just the other way around. So that they are just too lazy and cant be bothered to change it , and named it the convention current. lol

 

[ianc]

Anyone know why we havent changed conventional current to what actually happens?
Isn't science flogging a dead horse here?

hi there

i guess the main reason for using conventional current as opposed to electron flow is to make things conceptually simpler. an example of this is when you get to doing semiconductors, in one type of semiconductor (p-type) we understand the current in terms of the flow of "holes" or where the electron should have been. this makes it much easier to understand.

Also it provides a standard for understanding all forms of electric current where the charge carriers are not necessarily just electrons.

but yeah i agree with the "flogging a dead horse" thing in a way because for most applications it would make far more sense to use electron flow. the whole notion of conventions is a problem in all sciences, especially maths - eg which notation for derivatives is better: df/dx or f'(x)?

so it's just one of those things that you kind of accept, and then just work with because everyone else does

hope this helps!

 

[timmiitippii]

Very easy answer.

In CHemistry you have an electrochemical cell and an electrolytic cell. One has current forced into it(electrochemical/galvanic) and one actually generates current(electrolytic).

Here is where the deinfitions are not the same thing. In electrochemical anode=oxidising and cathode = reduction.

In electrolytic = cathode = oxidising and anode=reduction

Basically the cathode generates electrons and forces them out to which the CAThode ray tube in Physics is the same principle. i.e. you connect an induction coil which pumps out electrons then you are using an electrolytic cell.

It is along those lines...

Hope it helps.

actually reduction always occurs at the cathode and oxidation always occur at the anode (yes ppl an ox and red cat will always hold true)

The only thing that changes is the charge of these terminals either negative or positive.

My chem teacher basically explained it this way:
in chem (galvanic cells) the cells naturally uses their chemical potential energy to produce electrical energy through oxidation and reduction and exchange of electrons and all that.

BUt in physics (and also electrolytic cells), electrical energy is used to bring about chemical change, think of it as forcing the redox reaction backwards.
So if ur using electricity for any process, the cathode is always negative (electron builds up here) and anode is positive (electron moves towards here due to positive nature), but if ur using chemistry to produce electricity, the anode is negative (free electrons formed here) and cathode positive (electron used up here)
And since in physics its not really dealing with the chemistry, but the electrical energy, they regard cathode as negative terminal and anode as positive terminal.

Just remember that oxidation = anode and reduction = cathode and onli thing changed is the sign of the charge and u'll be fine

 

[Darrow]

I think I will just go with the Shut up and Accept it method philosphy
Until I learn otherwise in anycase