Redox and Electrode potentials Flashcards
what are the rules of balancing half equations
write down the species before an after reaction
balance any atoms apart from oxygen and hydrogen
if needed balance any oxygens with H2O and balance hydrogens with H+ ions
Balance charges with electrons
describe properties of transition elements
oxidise and reduce other substance
have variable oxidation states
have different colours depending on oxidation states
name two oxidising agents
potassium dichromate and acidified permanganate
how would you conduct an iodine- sodium thiosulfate solution
,measure out volume of KIO3 (25cm3)
add excess acidified potassium iodide solution to KIo3 solution
add solution into conical flask
add sodium thiosulfate into conical flask and look for pale yellow colour
as the colour change is diifiult to see add 2cm3 of starch
deep colour remains if iodine is still present in starch
when the blue colour disappears the iodine has been used up
what electrode is used if we have an inert but electrically conductive electrode
platinum
electrons always flow from a ____ reactive metal to a _____ reactive metal
more less
what is the salt bridge made from in an electrochemical cell
KNO3
if the electrode potential is negative then the half cell will undergo
oxidation
if the electrode is has a positive value then the half cell will undergo
reduction
NO PRoblem
which equation is flipped when constructing overall cll equations
oxidation (most negative)
how would you set top a standard hydrogen electrode
add H2
at 298K ans 100kpa
how do you calculate cell potential
reduced-oxidised
what are the advantages and disadvantages of furl cells
+ more efficient
hydrogen powered
more kinetic energy
don’t need recharge
only waste product is water
- highly flammable
expensive to transport
energy is required to make hydrogen in first place
all feasible reaction shave a positive what
e cell value
