Chemistry-Plz see this DrBob
posted by Anna .
I am sorry I do not know what happens the symbolism, so I just deleted the symbols. Is it works for you that deleted the symbols?
Using standard reduction potentials, calculate the standard Ecell, emf, for each of the following reactions. State if each reaction is spontaneous or nonspontaneous. (Use the below reactions AS WRITTEN, DO NOT REARRANGE ANY REACTIONS.) You must show the two half-reactions and balance the gain and loss of electrons.
a. H2(g) + I2(s) -> 2H^1+(aq) + 2I^1-(aq)
b. Ni^2+(aq) + 2Ce^5+(aq) -> Ni(s) + 2Ce^4+(aq)
c. 4Ce^3+(aq) -> Ce(s) + 3Ce^4+(aq) (Acid solution)
d. 2Al^3+(aq) + 3Cd(s) -> 2Al(s) + 3Cd^2+(aq)
H2(g) ==> 2H^+(aq) + 2e..Eo = 0 v
I2(s) + 2e ==> 2I^-(aq)..Eo = +0.535 v
H2(g) + I2(s) ==> 2H^+(aq) + 2I^-(aq)
Ecell as written = 0.535 v (0 + 0.535 = 0.535 v) and it is spontaneous since Ecell is positive. I have used each equation AS WRITTEN and I have not rearranged either half reaction; however, I think the problem contradicts itself in the first sentence. If I am to use standard reduction potentials then I must rearrange one of the half cells and that is forbidden in the problem. Anyway, you have the cell reaction as written, the cell potential as written, and that it is spontaneous as written. I hope this helps. The others are done the same way.
Thank you so so much!!!