Summary - Unit 14 - Redox II

REDOXII

HALF CELLS half
STANDARD HYDOGEN ELECTRODE (SHE
↳298k

rate
in an



eiee Chemical
↳ 100 UPA
↳ Imolan-3




standwa C




*
m
H2(g)

298k electrode potentials of
half cells can't be measured on their own !

use a reference SU E. .
= 0 00
.




OR ta Andverta
Sam
E
electrode




STANDARD ELECTRODE POTENTIAL

if using an ELECTRODE POTENTIALS

digit
EMF(Ecel) STEP 1 : clean metals with sandpaper




76
reduction b
removes surface impurities forward



way [cuzt(aq)
reaction


~
2(aq) + 2e- E2(s) = -
0 .




STEP 2 zeECs




W
kNO3
:
Wash surface with propanone + =
for
and wear gloves
enoves surface grease avoids
= 2n2+
-



2n(s) (aq) + 2e S
contamination
STEP 3
place each metal into a solution Cu2+(9)
:
+ 2n(s) = 2n2+ (aq) + (u(s)
containing the corresponding inn
2 Cusoy Cu electrode FACTORS :
temperature slow rare of reaction
-

reac
.
.
g for 10

concentration high activation
energy-may sto
pressure
↑


STEP 4 : link solutions using a salt bridge of
shift equilibrium
= shift cell potential value
file paper soared in UCI or KNO3
- this is why standard cond. are important to ensure
ions flow and the change balances the same values which allows us to make .
comparisons

STEP correct electrodes with wires , crocodile
G:
Excell Erreduced Eoxidised
= -




clips and a volmeter
.

Excell AS&
total


Excell < Ink




FUELCELLS supply of chemica




Mi
·

OT




Ohnote-tho (20
①
+ 2H20 + ye 40H cre


-Het 4 ② use


anod




e




H20t
overall :
02 + 212 +
2120
(they also work in acidic cond ) .




IODINE-S
↳ polymer electrolyte
Lion exchange
membrane
membranes
allow on - to pass ① measure approx . KlO3 to oxid
but not H2 or O2 6H
103 + 51 + -




ENERGY STORAGE CELLS




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