Question

PLEASE HELP: I'M ONLY NEEDED THE ANSWER TO NUMBER 3 :)

1. 3 Sn2+(aq) + 2 Al(s)??2 Al3+(aq) + 3 Sn(s). What is the voltage for this cell?

2. What is the Gibbs Free Energy for the above reaction assuming standard conditions?

3. What is the Gibbs Free Energy for the cell in question 1 if the Sn2+(aq) is [.15] and Al3+(aq) is [1.80]?

4. Describe what happens within the salt bridge between the two cells

Answer 1

Sn2+ + 2 e−<---> Sn(s) −0.13

Al3+ + 3 e− <---> Al(s) −1.662

Themost negative will oxidize then

Sn2+ + 2 e−<---> Sn(s) −0.13

Al(s) <--->Al3+ + 3 e− + 1.662

The balanced equation:

3Sn2+ + 6e−<---> 3Sn(s) −0.13

2Al(s) <--->2Al3+ + 6 e− + 1.662

3Sn+2 +2Al(s) --> 3Sn(s) + >2Al3+

Ecell = Ered + Eox = 1.662+-0.13 = 1.532 V

2. What is the Gibbs Free Energy for the above reaction assuming standard conditions?

G = -nF*E°Cell

G = -6*96500*1.532 = -887028 J

3. What is the Gibbs Free Energy for the cell in question 1 if the Sn2+(aq) is [.15] and Al3+(aq) is [1.80]?

Ecell = E°cell - 0.0592/n*logQ

For Q

3Sn+2 +2Al(s) --> 3Sn(s) + 2Al3+

Q = [Al3+]^2 / [Sn+2]^3

Q = (1.8^2)/(0.15)^3 = 960

n = 6 electrons

Ecell = E°cell - 0.0592/n*logQ

Ecell = 1.532 -0.0592/6*log(960)= 1.5025 V

4. Describe what happens within the salt bridge between the two cells

the salt bridge will bne the medium in which both electrolitical solutions will be connected and will be able to flow electrons through it.

If there is no bridge, then no electron flow, therefore no E°cell... you will see a 0 value