Electrochemistry

Question 2

Redox reaction

Answer 2

transfer of electrons from one molecule to another

Question 3

what do we mean by electric current

Answer 3

moving charged particles

Question 4

what can electron transfer do..

Answer 4

measure voltage and current

Question 5

sodium half reaction to form a positive ion

Answer 5

Na -> Na^+ + e^-

Question 6

oxidation

Answer 6

loss of electrons

Question 7

reduction

Answer 7

gain of electrons

Question 8

half reactions have an electrode potential…

Answer 8

it’s a voltage we can measure

Question 9

which electrode does reaction occur?

Answer 9

positive electrode (cathode)

Question 10

which electrode does oxidation occur?

Answer 10

negative electrode (anode)

Question 11

what reference point in electrochemistry?

Answer 11

standard hydrogen electrode

Question 12

reference electrode

Answer 12

silver and silver chloride (Ag/AgCl)

Question 13

Potentiometry

Answer 13

measuring voltage

Question 14

what do electrode potentials depend on?

Answer 14

the nature of its half reaction.
the concentrations of the molecules in the half reactions.

Question 15

Electrode potential is proportional to…

Answer 15

the natural log of the concentration

Question 16

electrochemsitry calibration graph

Answer 16

potential (on y-axis) and ln (ion conc) (on x-axis) forms a straight line going downwards

Question 17

how are we going to use potentiometry?

Answer 17

measure voltages using ion selective electrodes to determine concentrations

Question 18

most common ion selective electode

Answer 18

pH meter

Question 19

electrode on right is…

Answer 19

reference electrode

Question 20

electrode on left…

Answer 20

ion selective electrode

Question 21

inside the electrode there is…

Answer 21

an internal electrolyte (solution)

Question 22

Amperometry

Answer 22

the measure of electric current that flows when a constant external voltage is applied

Question 23

what gives us an electric current?

Answer 23

when electrons move from electron donor to electron receiver

Question 24

Polarography

Answer 24

measuring how the current flow varies as we change the voltage

Question 25

current(y) against voltage(x) graph

Answer 25

s shaped curve. start above 0, goes straight across but slightly up and the suddenly goes straight up and then flattens off again

Question 26

what does the graph allow you to measure

Answer 26

the jump on the curve identifies which ions are present through their half equations. and then you can work out its concentration