5.4 electrode potentials Flashcards
1
Q
define: standard electrode potential
A
The e.m.f. of a half-cell compared with a hydrogen halfcell
298K
1 mol dm-3
100kPa
2
Q
is a negative metal electrode reduced or oxidised in a cell?
A
oxidised
3
Q
why is a salt bridge used in an electrochemical cell?
A
allows ions to flow
4
Q
which direction do electrons flow?
A
negative to positive
5
Q
will conc of ions increase or decrease at the negative electrode in a cell?
A
increase
6
Q
overall reaction in an alkaline hydrogen/oxygen fuel cell?
A
7
Q
is the positive metal electrode reduced or oxidised in a cell?
A
reduced
8
Q
advantage of electrochemical cells
A
- for hydrogen cells, only waste product = water
- more efficient than convential combustion engines
- less pollution
9
Q
disadvantages of electrochemical cells
A
- production of cells uses toxic chemicals
- chemicals used are often flammable
10
Q
what do fuel cells do
A
produce energy by reacting fuel with an oxidant
11
Q
where are lithiam batteries found?
A
mobile phones
