topic 14 - further redox

Question 1

electrochemical cell

Answer 1

voltage is in reference to hydrogen
the difference in reducing power
salt bridge needed
+ve half is reduced

Question 2

potential difference

Answer 2

determined by the tendency to loose electrons

Question 3

cell equation

Answer 3

Zn | Zn^2+ || Cu^2+ | Cu
reduced | oxidised || oxidised | reduced

Question 4

standard conditions for ec cell

Answer 4

298 k
100kpa
1 mol dm

Question 5

standard hydrogen electrode

Answer 5

reference electrode
100kpa
hydrogen bubbling over
platnum foil in hcl
hydrogen ion conc of 1 mol dm-3
298k

Question 6

salt bridge

Answer 6

completes circut
contains conc solution of pottasium nitrate
allows movement of ions

Question 7

high resistance volt meter

Answer 7

used so salt bridge dosent interact
stops flow of electrons round external circuit

Question 8

e cell values

Answer 8

electromotive force
negative means equilibrium further to left
more readily looses electrons
best reducing agent

Question 9

postives of hydrogen oxygen fuel cell

Answer 9

harmful products
less reliant on fossil fuels
more efficient

Question 10

cell diagram (conventional)

Answer 10

pt (s) | R O || O R | pt (s)
if have plantum electrode pt
positive electrode on right
left side oxidised
right side reduced
ecell positive if positive on right
hydrogen electrode always on left

Question 11

sodium nitrate

Answer 11

NaNO3

Question 12

phosphoric(V) acid

Answer 12

H3PO4