A2 Electrochemistry

Question 1

redox reaction

Answer 1

the transfer of electrons

Question 2

the flow of electrons

Answer 2

is electrical current

Question 3

oxidation

Answer 3

electrons are lost

Question 4

reduction

Answer 4

electrons are gained

Question 5

what happens in half cells

Answer 5

electrons flow between half cells.

Question 6

what do half cells have

Answer 6

two different elements in different oxidation states

Question 7

electrode

Answer 7

the part of the cell where electrons flow in and out from

Question 8

what happens during oxidation

Answer 8

metal oxidises and ions are reduced

Question 9

half cell equation direction

Answer 9

it shows a reduction reaction where an ion forms a metal

Question 10

how can be gas be used in a redox electrochemical experiment?

Answer 10

the gas is bubble in the solution. the electrode used is platinum

Question 11

why is a metal electrode used for gases?

Answer 11

to give it a surface to react on

Question 12

why use platinum

Answer 12

it is inert
it is solid
it can conduct electricity

Question 13

explain what happens in a gas one

Answer 13

chlorine gas passes through a glass tube
the glass tube is at 100kpa and 298k and 1 mol
there are cl-.
the chlorine ions are oxidised and chlorine gas is reduced,
it is a dynamic equilibrium as the forward and backwards reaction are at the same rate and constant concentration,

Question 14

metal electrodes

Answer 14

metals surrounded by its solution

Question 15

gas electrodes

Answer 15

gas in its aqeous solution

Question 16

Redox electrode

Answer 16

two different ions of the same elements

Question 17

how to measure the potential of an electrode

Answer 17

the actual potential of the cell cannot be measured directly.
add another half cell with known potential, measure the potential difference and subtract from known potential

Question 18

electrochemical cell

Answer 18

two half cells

Question 19

SHE

Answer 19

standard hydrogen electrode potential difference of 0 acts as a universal reference .
the standard which we compare the other potentials to.

Question 20

how to set up electrochemical cell

Answer 20

1. The metals are joined by a wire
2. a piece of paper soack in concentrated kno3 is dipped in the solution to form a salt bridge
   3, voltmeter

Question 21

salt bridge

Answer 21

paper soaked in unreactive ions

agar

Question 22

why use a high restitance voltmeter

Answer 22

to measure how hard electronsa re being pushed

to measure the potential of the electron flow

Question 23

standard electron potential

Answer 23

the emf that is generated when connected to a standard hydrogen electrode in 298k, 100kpa and 1 mol dm-3

Question 24

emf

Answer 24

how much force electrons are pushed asround the circuit

Question 25

reducing cell

Answer 25

cathode

Question 26

oxidising cell

Answer 26

anode

Question 27

what way to electrons slow

Answer 27

negative to postitive - there is a force of attraction