-
1. 1 Definitions
Redox reaction transfer of electrons
: a reaction
involving the
Oxidation : loss of electrons
Reduction
gain of electrons
:
Oxidising agent : a substance that accepts electrons
Reducing agent : a substance that donates electrons
1. 2 Half reactions
-
Oxidation half reaction
µ →
Mt + e
reducing it left M
agent
Reduction half reaction
-
N + e → N
oxidising} it is
adding to N
agent
the oxidation states of metals and non
1. 3 Recognising metals
-
Oxidation states of metals
Fe )
" "
Zero oxidation state =
solid metals ( Nd Ag Cu
, , ,
In ,
" "
Fe )
Agt Fest
2T
positive oxidation state =
ions in solution ( Nat , ,
Cu ,
Zn . ,
-
part of a salt
Oxidation states of non -
metals
" "
Zero oxidation state ( C1 2,02 Hz )
,
positive / oxidation state ICI 05 Ht part of )
-
negative a salt in a solution
-
,
1. 4
Examples of redox reactions
1. 2N ( s ) + CUZ ( Ag ) +
→ CU (s) +
Znzt ( ag )
CU 1st
Agt ( ag ) 2
Ag ( S )
+
2 .
+ 2 → CUZ lag I +
,1. 5 Standard Electrode Potentials (SEP) table
,2. Half Cells -
*
spectator ions d not take part in the electron transfer
2. 1 Structure of Half Cells -
↳
half -
cell consists of an electrode dipped into an electrical
conducting solution (electrolyte)
↳ an is a substance that can conduct
electrolyte electricity by forming free ions when molten
or dissolved in solution
↳ enters / leaves an
an electrode is a conductor
through which
electricity object substance
,
or region (made of metal /
graphite)
↳ a
half cell -
will contain an element in two different oxidation states 12 different charges )
↳
an equilibrium will exist between the two oxidation states
2. 1 Gas Half cells
↳ consist of with its ions
a
gas in equilibrium
↳
gas is pumped into the cell in a
glass tube which has a piece of platinum in
it ( the electrode)
↳
gas absorbs onto ( sticks onto the surface of) the platinum foil as well as
bubbling
the solution
through
↳ the actual electrode is the platinum wire not the
gas
2. 3 The Standard Hydrogen Electrode (SHE/
↳ a
hydrogen half -
cell which is assembled under standard conditions which ,
are :
-
Concentration of solutions : 1 MOI dm-3 .
-
Temperature 25°C :
-
Pressure of gases : 1 Atm
( H2 ) bubbled
of hydrogen gas g hydrogen
↳ consists
through an
electrolyte contain ions
( Ht ) under standard solutions
↳a
platinum ( Pt ) electrode is used as it is unreactive and takes no part in the reaction
↳ Pt electrode provides a metal surface where redox reactions can take place
1. 1 Definitions
Redox reaction transfer of electrons
: a reaction
involving the
Oxidation : loss of electrons
Reduction
gain of electrons
:
Oxidising agent : a substance that accepts electrons
Reducing agent : a substance that donates electrons
1. 2 Half reactions
-
Oxidation half reaction
µ →
Mt + e
reducing it left M
agent
Reduction half reaction
-
N + e → N
oxidising} it is
adding to N
agent
the oxidation states of metals and non
1. 3 Recognising metals
-
Oxidation states of metals
Fe )
" "
Zero oxidation state =
solid metals ( Nd Ag Cu
, , ,
In ,
" "
Fe )
Agt Fest
2T
positive oxidation state =
ions in solution ( Nat , ,
Cu ,
Zn . ,
-
part of a salt
Oxidation states of non -
metals
" "
Zero oxidation state ( C1 2,02 Hz )
,
positive / oxidation state ICI 05 Ht part of )
-
negative a salt in a solution
-
,
1. 4
Examples of redox reactions
1. 2N ( s ) + CUZ ( Ag ) +
→ CU (s) +
Znzt ( ag )
CU 1st
Agt ( ag ) 2
Ag ( S )
+
2 .
+ 2 → CUZ lag I +
,1. 5 Standard Electrode Potentials (SEP) table
,2. Half Cells -
*
spectator ions d not take part in the electron transfer
2. 1 Structure of Half Cells -
↳
half -
cell consists of an electrode dipped into an electrical
conducting solution (electrolyte)
↳ an is a substance that can conduct
electrolyte electricity by forming free ions when molten
or dissolved in solution
↳ enters / leaves an
an electrode is a conductor
through which
electricity object substance
,
or region (made of metal /
graphite)
↳ a
half cell -
will contain an element in two different oxidation states 12 different charges )
↳
an equilibrium will exist between the two oxidation states
2. 1 Gas Half cells
↳ consist of with its ions
a
gas in equilibrium
↳
gas is pumped into the cell in a
glass tube which has a piece of platinum in
it ( the electrode)
↳
gas absorbs onto ( sticks onto the surface of) the platinum foil as well as
bubbling
the solution
through
↳ the actual electrode is the platinum wire not the
gas
2. 3 The Standard Hydrogen Electrode (SHE/
↳ a
hydrogen half -
cell which is assembled under standard conditions which ,
are :
-
Concentration of solutions : 1 MOI dm-3 .
-
Temperature 25°C :
-
Pressure of gases : 1 Atm
( H2 ) bubbled
of hydrogen gas g hydrogen
↳ consists
through an
electrolyte contain ions
( Ht ) under standard solutions
↳a
platinum ( Pt ) electrode is used as it is unreactive and takes no part in the reaction
↳ Pt electrode provides a metal surface where redox reactions can take place
