#21. The speed of the reaction. This is because something can be thermodynamically favored, ex. a metal turning into another. This topic tells us that it WILL happen, but does not state the speed of it doing so.

Thanks so much! One last question.



When you balance the half reactions to get the correct number of electrons, how do you come up with the correct number of transferred electrons (n)?

you write redox half equations:

4Fe^3+ +4e- --> 4Fe^2+

2Sn^2+ --> 2Sn^4+ + 4e-

balances perfectly so its relatively simple

you just look at the change of oxidation state of the metals

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just clarification for q23:

in 23 i convert to kjmol-1 so delta H and T*delta S are in the same units (dont just blindly convert, make sure they will be the same units)

This post was edited by ArnoldChlamydia on Dec 11 2013 10:02pm

I have

2Sn^2+ --> 2Sn ^4+ +2e-
4Fe^3+ + e- ---> 4Fe^2+

I don't understand how you get the 4 for the transferred electrons.

because of the coefficients:

4 Fe^3+ +4e- ---> 4 Fe^2

imagine it as:

Fe^3+ + e- --> Fe^2+

this happens 4 times so 4e-

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2Sn^2+ --> 2Sn^4+ + 4e-

imagine it as:

Sn^2+ --> Sn^4+ + 2e-

this happens twice so 4e-