electrode potential and cells

Question 1

what are the three type of cells

Answer 1

metal/metal ion
non metal/non metal
metal ion/metal ion

Question 2

what is a half cell

Answer 2

compromises of an element in two oxidation states

Question 3

what is in the simplest half cell

Answer 3

has a metal placed in an aqueous solution of its ions

Question 4

where is the equilibrium

Answer 4

on the surface if the metal between the different oxidation state of the metals

Question 5

how is the equilibrium written

Answer 5

in reduction form with the electrons always on the left

Question 6

what happens if the equilibrium lies on the left

Answer 6

more electrons are released
more negative electrode
more oxidation

Question 7

what happens if the equilibrium lies on the right

Answer 7

more electrons are gained
more reduction
more positive

Question 8

how is e cell value calculated

Answer 8

obtained by comparing a cell to the standard hydrogen electrode she

Question 9

what is the units for the e cell

Answer 9

volts

Question 10

what is the she

Answer 10

it is a standard reference used as a comparison tool to compare potential to that of the she

Question 11

what does the she have a potential of

Answer 11

o.oo v

Question 12

describe the conditions of a standard hydrogen electrode

Answer 12

hydrogen gas bubbles
1mol/dm3
29k
100kpa

Question 13

how is the platinum structured

Answer 13

coated with finely divided platinum which as a conducting surface

Question 14

why is platinum used

Answer 14

it is unreactive and inert so doesn’t make a potential difference but also conducts electricity

Question 15

what are properties of platinum

Answer 15

it is porous so it can absorb hydrogen gas

Question 16

what exists on the surface of platinum

Answer 16

an equilibrium between hydrogen and hydrogen ions

Question 17

why is standard conditions required

Answer 17

otherwise the position of redox equilibroium will change with conditions

Question 18

how else can half cells be made

Answer 18

by two aqeous ions of the same element for example fe2+ and fe3+

Question 19

what must be ensure

Answer 19

that the concentration of both ions are 1mol/dm

Question 20

what is used as the conducting surface

Answer 20

platinum and metal surface

Question 21

what is an electrochemical cell

Answer 21

it is formed from one half cell that releases electron and one half cell that gains electrons

Question 22

what are connected to the half cells

Answer 22

a wire and a salt bridge

Question 23

what does a wire allow

Answer 23

allows electrons to be transferred between the two half cells

Question 24

what does the salt bridge provide

Answer 24

an electrical connection between the two solutionsq

Question 25

what does this allow

Answer 25

ions to move through it and complete the circuit

Question 26

how is a salt bridge made

Answer 26

using filter paper soaked in aqueous solution of ionic compound

Question 27

what must the ionic compound be and give an example

Answer 27

react with either half cell solution or electrodes so kno3 or nh4no3

Question 28

why will sodium chloride not be suitable for a salt bridge of a cell

Answer 28

as the cl- will react with some metal ions to form complexes / precipitates

Question 29

why would a wire not be a suitable salt bridge

Answer 29

a wire would set up its own electrode system with the solution

Question 30

where is the voltmeter found

Answer 30

between two half cells

Question 31

what must the voltmeter be and why

Answer 31

a very high resistance to stop the current from flowing through the circuit

Question 32

what does this allow

Answer 32

the maximum potential difference can be measured

Question 33

what happens to the reaction when there is a high resistance

Answer 33

no reaction takes place as the current stopped from flowing

Question 34

what happens if the voltmeter is replaced by a bulb

Answer 34

a current flows

Question 35

what happens to this current

Answer 35

it lead to reactions occurring separately at each electrode

Question 36

what will happen to the voltage

Answer 36

it will fall to zero as the reactant concentration decreased and become the same at each electrode

Question 37

HOW DO WE DRAW THE CELL

Answer 37

the more negative half cell is always on the right ROOR