Lead acid accumalator

[lacoste]

How do I derive two half equations from the overal equation.

I don't know where to split it.

And I was told that we dont need to rote learn it, is this true?

[thisongaintgottaname]

work on their oxidation number is the fastest way for me. count the oxidation number of Pb on each side of the equation then determine which specie has been oxidised/reduced.
then try to use your unit 3 knowledge of writing a half equation to complete the two half-equations.

[kendraaaaa]

Yes you don't need to memorize them. This is how I was taught it

This is the overall equation:



Next, you 'expand' all of the molecules as so:



From this you can tell that and will be the reactants, hence they will be in their own seperate equations. Firstly lets do lead:




From this you can see how one half equation is derived. Lets extract this from the overall equation. (Two electrons on the right balance the charge)



Since the electrons are located on the right hand side of the equation we know that this is the oxidation reaction hence it is at the anode. I think from here you can do the other half equation, if not I'll be happy to finish this off.

[c23]

from the above example
the way my teacher taught me
was to split them first

as it is obvious that :

Pb_(s) -----> PbSO_4(s)
and
PbO_2(s) ----->PbSO_4(s)

then just add in whats appropriate using the equation given
to build up the half eqautions

but some eqautions you should remember like the alkaline fuel cell half eqns