Electrochemistry

Question 1

predict products

Answer 1

• cation that is most easily reduced is discharged (high E⦵)
• anode that is most easily oxidised
• when molten = no H or OH
• when concentrated, no OH- for anion

Question 2

SEP

Answer 2

the voltage produced when s standard half cell is connected to a standard hydrogen electrode under sc

Question 3

SCP

Answer 3

the difference in standard SEP between two half cells

Question 4

SHE

Answer 4

hydrogen gas at 101kPa with H+ ions of concentration 1.00moldm-3
Pt electrode covered Pt black in contact with hydrogen gas and H+ ions

Question 5

calcualte SCP

Answer 5

difference between two

Question 6

direction of electron flow

Answer 6

from negative to positive
e.g Fe = +0.77
Cu = +0.34
from Cu to Fe

Question 7

feasibility

Answer 7

add the two values

Question 8

Nernst equation

Answer 8

E = E⦵ + 0.059/z log([oxidised]/[reduced])
for metal ions:
E = E⦵ + 0.059/z log([oxidised])

Question 9

When one half cell is diluted with water, what happenes to the voltage

Answer 9

more positive

-half cell less positive so the difference between voltages increase and E increases!

Question 10

conc of copper ions increase, what happens to half cell

Answer 10

E value increase!

Question 11

conc of copper ions increase, what happens to complete cell

Answer 11

decrease as copper is worse at gaining so going other direction

Question 12

conc of copper ions increase, why does the direction not change because of the concentration increase?

Answer 12

When NOT under sc, if difference is greater than 0.30 V, remains unaltered.