CH 1 electro chem

Oxidation numbers

1. OS of individual atoms = 0

2. total OS of alla toms in:

3. - neutral species = 0

4. ion = total charge of ion

5. in its compund OS of group 1 metal = +1, group 2 = +2,

6. F= -1

7. H= +1

8. O = -2

9. group 17 = -1

10. group 16= -2

11. group 15 = -3

12. if there is an element more electronegative that O then o = +2

OS for complex compunds

1 . identify ligand charges (ex: NH3 = 0)

2 write ox equation

electro chemistry

Exchange of chemical energy (rxn) and electrical energy (current)

oxidation

Loss of e-s (LEO)

reduction

Gain fo e-s (GER)

how to balnce redox

1. determine which is reduction and which is oxidation and split into two half rxns

2. blance main elements of rns (all atoms except o and H

3. Then balance O by adding H2O

4. then balance H by addign H+, where ever H is electons will follow

5. Balance charge with e-s, (look at overall charge of each side, including H+ charge) place e-s with wherevver H+ is at

6. blance e-s of both eqautiosn with least common multiple so they calnce out

7. then add the sides and cancel out common species

Acidic conditions redox

For acidc conditions follow like normal

Basic conditions redox rxns

For basc conditions, after step 5…

6. Add OH- on both sides to get rid of H+

7. convert H+ to H2O via (H+ + OH- → H2O)

8. cancle out waters

9. make sure t multi the e-s and equatiosn so they the same - then after that combien bot equations, cancleing out out common specie

or

after step 4 convert thoese directly to OH- IF there is no H+

galvanic cells

PArts of galvanic cells

how to draw galvanci cells

short hand notation of galvanic cells

How to find E^ocell / voltage

1. identify which half rxn us reduction and which sis oxidation

2. look up at E^o values form standard reduction vlaues - tables always list reduction potential, even if rxn is ox don’t flip E^o value

3. use equation - anode = ox and cathode = oxidation

4. Don;t mutliply the half rxns

if both E^o same ?

then flip the one that will not make the final value negative (smaller one)