ELECTRODE POTENTIAL

Question 1

Half cell

Answer 1

a half cell is one half of an electrochemical cell. they can be constructed of a metal dipped in its own ion or a platinum electrode in 2+ aqueous ions.

Question 2

why do we use platinum electrode

Answer 2

because it is inert and electrically conductive metal.

Question 3

electrochemical cells

Answer 3

electrochemical cells are made up of two half cells joined together by a wire, a voltmeter and a salt bridge. there are always two reaction occuring oxidation and reduction therefore it is a redox reaction.

Question 4

what is a salt bridge

Answer 4

strip of a filter paper soaked in kno3 solution.

Question 5

how do electrons flow between half cells

Answer 5

always from a high recating metal to the lower one.
example zinc gets oxidised and gets thinner whereas copper gets reduced and becomes thicker.

Question 6

electrode potential or delta e

Answer 6

each half cell has its own electrode potential. it tells us how easily the half cell gives up electrons ( becomes oxidised)

Question 7

how do we write up the equations

Answer 7

always in reduced form. never in oxidised form.n

Question 8

acronym we use

Answer 8

NO PROBLEM
the most negative value is oxidised meaning that equation needs to be flipped
and the most positive value is the one getting reduced.

Question 9

SHE stands for?

Answer 9

STANDARD HYDROGEN ELECTRODE

Question 10

SHE ( STANDARD HYDROGEN ELECTRODE)

Answer 10

SHE is a reference for measuring standard electrode potential.

Question 11

value of SHE

Answer 11

0.00VOLTS

Question 12

What affects the value of an electrode potential

Answer 12

temperarure, pressure and concentration

Question 13

standard conditions?

Answer 13

temperature – 298K
Pressure – 100Kpa
concentration– 1mol per dm -3.

Question 14

note

Answer 14

when we say concentration we actually mean, 1 mol dm-3 of H+ ion not actually acid. if we use h2so4, then we use 0.5 mol dm-3 since its a diprotic acid.

Question 15

electro chemical series

Answer 15

electro chemical series is a list of half cell reactions and their standard electrode potentials.

Question 16

oxidisation and oxiding agent

Answer 16

oxifdation is losing electron and oxidising agent is gaining electron

Question 17

reduction ans reducing agent

Answer 17

reduction is gaining electron and reducing agent is losing electron

Question 18

note for electro chemical series

Answer 18

in an electro chemical series, we always find the oxidising agent in the left hand side and the reducing agent always on the right hand side.

Question 19

standard cell potential

Answer 19

e reduced - e oxidised.

Question 20

cell notation

Answer 20

standard way of representing cells in chemistry.

Question 21

cell notation format

Answer 21

reduced form l oxidised form ll oxidised form l reduced form

where ll represents a salt bridge
and l represents a physical state change.

Question 22

what do we do if we have two aqueous ions

Answer 22

we use a comma

Question 23

batteries

Answer 23

batteries are electro chemical cells that exists in two forms : rechargeable and non rechargeable.

Question 24

example of rechargeable battery

Answer 24

lithium ion batteries used in phone etc.

Question 25

note

Answer 25

mobile phone uses a lithium ion cell havin the folowing components
electrode A - LITHIUM COBALT OXIDE
electrode B - GRAPHITE
ELECTRODE - lithium salt dissolved in organic solvent.

Question 26

steps to find a reaction feasibility

Answer 26

1. from the electro chemical series find out the oxidised reaction, remember NO PROBLEM (most negative is oxidised)
2. after finding the oxidised equation, always flip it,(it will be in reduced form in the equation)
3. after flipping the oxidised equation, make sure number of electrons are equal in both reactions and cancel out the electrons.
4. write out the remaining bits to see if they match.
5. you can also find electrode potential with the formula
   reduced - oxidised ( acronym redox)
6. if the value is positive, it means that the reaction is feasible.