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Oxidation Numbers, ox # - SCH4U1-CCVI - home + 3 e- Au +1.50 Ce4+ + e-1 Ce3+ +1.44 ClO4 1- + 8 H+ +...

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Oxidation Numbers, ox # are _____ or _____ numbers assigned to each _______ or ____ assuming that the _____________ are transferred ________________ from the ______ electronegative element to the _______ electronegative element. ________________ now mimic ________ systems. ox # are written _______ followed by _________ and are assigned using the following: Oxidation Number Rules The ox # of an ______ in it’s pure form, (eg. Pb (s) , O 2(g) ) is ____. The ox # of a ____________ _____ is equal to the _________ on that ______. eg. Cl 1- The algebraic ____ of the oxidation numbers in a ________ polyatomic compound is ___. eg. Mg 3 N 2 Fe(NO 3 ) 3
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Page 1: Oxidation Numbers, ox # - SCH4U1-CCVI - home + 3 e- Au +1.50 Ce4+ + e-1 Ce3+ +1.44 ClO4 1- + 8 H+ + 8 e- Cl1- + 4 H2O +1.39 Cl2 + 2 e- 2 Cl- +1.36 2 HNO 2 + 4 H+ + 4 e- N O + 3 H O

Oxidation Numbers, ox #

are _____ or _____ numbers assigned to each _______ or

____ assuming that the _____________ are transferred

________________ from the ______ electronegative

element to the _______ electronegative element.

________________ now mimic ________ systems.

ox# are written _______ followed by _________ and are

assigned using the following:

Oxidation Number Rules

The ox# of an ______ in it’s pure form, (eg. Pb(s), O2(g) )

is ____.

The ox# of a ____________ _____ is equal to the _________ on that ______.

eg. Cl1-

The algebraic ____ of the oxidation numbers in a ________ polyatomic compound is ___.

eg. Mg3N2 Fe(NO3)3

Page 2: Oxidation Numbers, ox # - SCH4U1-CCVI - home + 3 e- Au +1.50 Ce4+ + e-1 Ce3+ +1.44 ClO4 1- + 8 H+ + 8 e- Cl1- + 4 H2O +1.39 Cl2 + 2 e- 2 Cl- +1.36 2 HNO 2 + 4 H+ + 4 e- N O + 3 H O

The most common ox# for O is ___, in peroxides it is ___,

and in compounds with fluorine it is ___. The most common ox# of H is ___, in metal hydrides it is

___. The algebraic ______ of the oxidation numbers in a

polyatomic _____ is equal to the _________ on the ____.

eg. Cr2O

7

2-

Assign the ox# to the most _______________ element __ Determine the ______ charge for that element Considering the charge on the ion or neutral compound,

find the total charge for the other element, then its ox #. In compounds of _______________, the ox# of the

______ electronegative atom is ______ and the ox# of the

______ electronegative atom is _______.

eg. CO2 In a covalent bond, the more ________________ atom

takes _____ the ____________ in the bond.

Page 3: Oxidation Numbers, ox # - SCH4U1-CCVI - home + 3 e- Au +1.50 Ce4+ + e-1 Ce3+ +1.44 ClO4 1- + 8 H+ + 8 e- Cl1- + 4 H2O +1.39 Cl2 + 2 e- 2 Cl- +1.36 2 HNO 2 + 4 H+ + 4 e- N O + 3 H O

Energy Transfer Theory

Chemical reactions _________ with the ______________

of __________.

Often, this energy is _____ noticeable as it doesn’t

involve a ___________ change or the production of

________ or _______.

This is true of ____________ reactions, where the

___________ switch between entities with no

___________ change in _________.

To examine the energy ____________ we _________ the

chemical reaction into ___ separate reactions called _____

____________.

For:

Net ionic equation

Page 4: Oxidation Numbers, ox # - SCH4U1-CCVI - home + 3 e- Au +1.50 Ce4+ + e-1 Ce3+ +1.44 ClO4 1- + 8 H+ + 8 e- Cl1- + 4 H2O +1.39 Cl2 + 2 e- 2 Cl- +1.36 2 HNO 2 + 4 H+ + 4 e- N O + 3 H O

Half reactions

The energy _________ is the electron ______________ –

______________

Redox reactions require the ______________ reaction

_________________________ to occur simultaneously

with the _______________ reaction

_________________________

Redox – ____________________________

_________ goes __________

______ _______

Page 5: Oxidation Numbers, ox # - SCH4U1-CCVI - home + 3 e- Au +1.50 Ce4+ + e-1 Ce3+ +1.44 ClO4 1- + 8 H+ + 8 e- Cl1- + 4 H2O +1.39 Cl2 + 2 e- 2 Cl- +1.36 2 HNO 2 + 4 H+ + 4 e- N O + 3 H O

Balancing REDOX Reactions 1. Assign ___________ ____________ (ox. #) to ______ element in the

rxn and __________ the species being ____________ and ____________.

2. Write separate ______ ____________ (1/2 rxn), for the

______________ (ox.) and _____________ (red.) processes. 3. Balance the ___________ that undergo _____________ or

______________. 4. Add the total _________ gained or lost in _______ ox. or red. rxn.

5. Multiply each _________ so that once combined, the total # of e-s ______ out.

6. Combine the _________. 7. Balance the net ___________ (due to ions) using _____ ions to one

side (for acidic sol’n) or with _______ ions (for basic sol’n). 8. Add _______ to balance ____ and ____. 9. Check that the final eq’n is ________________.

Page 6: Oxidation Numbers, ox # - SCH4U1-CCVI - home + 3 e- Au +1.50 Ce4+ + e-1 Ce3+ +1.44 ClO4 1- + 8 H+ + 8 e- Cl1- + 4 H2O +1.39 Cl2 + 2 e- 2 Cl- +1.36 2 HNO 2 + 4 H+ + 4 e- N O + 3 H O
Page 7: Oxidation Numbers, ox # - SCH4U1-CCVI - home + 3 e- Au +1.50 Ce4+ + e-1 Ce3+ +1.44 ClO4 1- + 8 H+ + 8 e- Cl1- + 4 H2O +1.39 Cl2 + 2 e- 2 Cl- +1.36 2 HNO 2 + 4 H+ + 4 e- N O + 3 H O

Predicting Redox Reactions

Redox Rxn

occur due to the ____________ of e- from ________

substance to _______________.

is a ________________ of e- between _____________.

if ______ substance ________ e- from another, a

_______________________ rxn _____________. eg. Cu + 2Ag+ ↔ Cu2+ + 2Ag

Reducing agents (RA)

a substance that __________ e- to another substance and

undergoes __________________. Oxidizing agents (OA)

a substance that __________ e- to another substance and

undergoes __________________. eg. Cu + 2Ag+ ↔ Cu2+ + 2Ag

Page 8: Oxidation Numbers, ox # - SCH4U1-CCVI - home + 3 e- Au +1.50 Ce4+ + e-1 Ce3+ +1.44 ClO4 1- + 8 H+ + 8 e- Cl1- + 4 H2O +1.39 Cl2 + 2 e- 2 Cl- +1.36 2 HNO 2 + 4 H+ + 4 e- N O + 3 H O

rxns are listed as ____________, S = Strong, W = Weak.

SOA OA1 + ne- ↔ RA1 WRA

WOA OA2 + ne- ↔ RA2 SRA spontaneous rxns occur only if the ______ is

____________ and to the _________ of the ______. For spontaneous rxn:

eg. Will a mixture of aqueous chromium (II) nitrate and tin (II) nitrate react and if so what is the overall equation?

List all species ________ determine the ________, _____________ on the _______ and the ________, ________ on the _________ on the REDOX table

Page 9: Oxidation Numbers, ox # - SCH4U1-CCVI - home + 3 e- Au +1.50 Ce4+ + e-1 Ce3+ +1.44 ClO4 1- + 8 H+ + 8 e- Cl1- + 4 H2O +1.39 Cl2 + 2 e- 2 Cl- +1.36 2 HNO 2 + 4 H+ + 4 e- N O + 3 H O

eg. Create ½ rxns from the following reaction data and place in order of strongest to weakest OA:

Ion/metal Zn Pb Ag I1-

Zn2+

Pb2+

Ag+

I2

Page 10: Oxidation Numbers, ox # - SCH4U1-CCVI - home + 3 e- Au +1.50 Ce4+ + e-1 Ce3+ +1.44 ClO4 1- + 8 H+ + 8 e- Cl1- + 4 H2O +1.39 Cl2 + 2 e- 2 Cl- +1.36 2 HNO 2 + 4 H+ + 4 e- N O + 3 H O

eg. Create ½ rxns from the following reaction data and place in order of strongest to weakest OA:

Cu2+ + Pb Cu + Pb2+ Ag + Br2 AgBr

Ag+ + Cu Ag + Cu2+ Au + Br2 no rxn

eg. Create ½ rxns from the following reaction data and place in order of strongest to weakest OA:

W + M2 W2+ + M1- Y2+ + Z Y + Z2+

X + M2 no rxn W + Y2+ no rxn

X2+ + Z X + Z2+

Page 11: Oxidation Numbers, ox # - SCH4U1-CCVI - home + 3 e- Au +1.50 Ce4+ + e-1 Ce3+ +1.44 ClO4 1- + 8 H+ + 8 e- Cl1- + 4 H2O +1.39 Cl2 + 2 e- 2 Cl- +1.36 2 HNO 2 + 4 H+ + 4 e- N O + 3 H O

Standard Reduction Potentials ( also p 805) E° (volts)

F2 + 2 e- 2 F-1 +2.87

S2O82- + 2 e- 2 SO4

2- +2.01

Co3+ + e-1 Co2+ +1.81

Pb4+ + 2 e-1 Co2+ +1.80

H2O2 + 2 H+ + 2 e- 2 H2O +1.77

Au+ + e-1 Au +1.69

PbO2 + SO42- + 4 H+ + 2 e- PbSO4 + 2 H2O +1.69

MnO41- + 8 H+ + 5 e- Mn2+ + 4 H2O +1.51

Au3+ + 3 e- Au +1.50

Ce4+ + e-1 Ce3+ +1.44

ClO41- + 8 H+ + 8 e- Cl1- + 4 H2O +1.39

Cl2 + 2 e- 2 Cl- +1.36

2 HNO2 + 4 H+ + 4 e- N2O + 3 H2O +1.30

Cr2O72- + 14 H+ + 6 e- 2 Cr3+ + 7 H2O +1.23

O2 + 4 H+ + 4 e- 2 H2O +1.23

MnO2 + 4 H+ + 2 e- Mn2+ + 2 H2O +1.22

2 IO31- + 12 H+ + 10 e- I2 + 6 H2O +1.20

Br2 + 2 e- 2 Br-1 +1.07

AuCl41- + 3 e- Au + 4 Cl- +1.00

Hg2+ + 2 e- Hg +0.85

ClO1- + H2O + 2 e- Cl1- + 2 OH-1 +0.84

Ag+ + e- Ag +0.80

NO31- + 2 H+ + e- NO2 + H2O +0.80

Hg22+ + 2 e- 2 Hg +0.79

Fe3+ + e- Fe2+ +0.77

O2 + 2 H+ + 2 e- H2O2 +0.70

MnO41- + 2 H2O + 3 e- MnO2 + 4 OH-1 +0.60

I2 + 2 e- 2 I- +0.54

Cu+ + e- Cu +0.52

O2 + 2 H2O + 4 e- 4 OH- +0.40

Cu2+ + 2 e- Cu +0.34

SO42- + 4 H+ + 2 e- SO2 + 2 H2O +0.18

SO42- + 4 H+ + 2 e- H2SO3 + H2O +0.17

Sn4+ + 2 e- Sn2+ +0.15

Page 12: Oxidation Numbers, ox # - SCH4U1-CCVI - home + 3 e- Au +1.50 Ce4+ + e-1 Ce3+ +1.44 ClO4 1- + 8 H+ + 8 e- Cl1- + 4 H2O +1.39 Cl2 + 2 e- 2 Cl- +1.36 2 HNO 2 + 4 H+ + 4 e- N O + 3 H O

Cu2+ + e- Cu+ +0.15

S + 2 H+ + 2 e- H2S +0.14

AgBr + e- Ag + Br-1 +0.07

2 H+ + 2 e- H2 +0.00

Fe3+ + 3 e- Fe -0.04

Pb2+ + 2 e- Pb -0.13

Sn2+ + 2 e- Sn -0.14

AgI + e- Ag + I-1 -0.15

Ni2+ + 2 e- Ni -0.26

Co2+ + 2 e- Co -0.28

H3PO4 + 2 H+ + 2 e- H3PO3 + H2O -0.28

Tl+ + e- Tl -0.34

PbSO4 + 2 e- Pb + SO42- -0.36

Se + 2 H+ + 2 e- H2Se -0.40

Cd2+ + 2 e- Cd -0.40

Cr3+ + e- Cr2+ -0.41

Fe2+ + 2 e- Fe -0.45

S + 2 e- S2- -0.48

Ga3+ + 3 e- Ga -0.53

Ag2S + 2 e- 2 Ag + S2- -0.69

Cr3+ + 3 e- Cr -0.74

Zn2+ + 2 e- Zn -0.76

Te + 2 H+ + 2 e- H2Te -0.79

2 H2O + 2 e- 2 OH-1 + H2 -0.83

Cr2+ + 2 e- Cr -0.91

Se + 2 e- Se2- -0.92

SO42- + H2O + 2 e- SO3

2- + 2 OH-1 -0.93

Te + 2 e- Te2- -1.14

Mn2+ + 2 e- Mn -1.18

V2+ + 2 e- V -1.19

Al3+ + 3 e- Al -1.66

Ti2+ + 2 e- Ti -1.75

Mg2+ + 2 e- Mg -2.37

Ce3+ + 3 e- Ce -2.48

Na+ + e- Na -2.71

Ca2+ + 2 e- Ca -2.87

Ba2+ + 2 e- Ba -2.91

Cs2+ + 2 e- Cs -2.92

Ra2+ + 2 e- Ra -2.92

K+ + e- K -2.92

Li+ + e- Li -3.00

Page 13: Oxidation Numbers, ox # - SCH4U1-CCVI - home + 3 e- Au +1.50 Ce4+ + e-1 Ce3+ +1.44 ClO4 1- + 8 H+ + 8 e- Cl1- + 4 H2O +1.39 Cl2 + 2 e- 2 Cl- +1.36 2 HNO 2 + 4 H+ + 4 e- N O + 3 H O

Electrochemical Cells

(Galvanic, Voltaic, Electric)

the ___________ reactions are occurring _____________

and are _________ by a _______

the e- _________ occurs through this ___________ circuit

the ______ difference ______________ is manifested as

__________ __________.

X+Y+

K+ NO3-

Salt Bridge

As the cell proceeds:

Cathode Anode

mass of electrode

Solution electrical charge

Ions from salt bridge

Page 14: Oxidation Numbers, ox # - SCH4U1-CCVI - home + 3 e- Au +1.50 Ce4+ + e-1 Ce3+ +1.44 ClO4 1- + 8 H+ + 8 e- Cl1- + 4 H2O +1.39 Cl2 + 2 e- 2 Cl- +1.36 2 HNO 2 + 4 H+ + 4 e- N O + 3 H O

Cell Shorthand Notation eg. For the Zn/Cu cell: ____________________________ Conventions: the │ notation indicates a phase ______________ where

the _______________ and _________________ are in

physical contact. the ║ notation represents the ______ __________ or

_________ ____________ if additional _____________ are ____________ or

specific ___________ are ___________, they are written

with the _____________ separated by a ___________ or

a _______________. if the cell has no _______ for the electrode, __________

electrodes _________ or __________ are used:

___________________________________________ standard cells are __________ at _________ all ______ sets of information – REDOX equation, cell

diagram and the cell notation are related and if ___ is

provided, the other ____ should be able to be _________.

Page 15: Oxidation Numbers, ox # - SCH4U1-CCVI - home + 3 e- Au +1.50 Ce4+ + e-1 Ce3+ +1.44 ClO4 1- + 8 H+ + 8 e- Cl1- + 4 H2O +1.39 Cl2 + 2 e- 2 Cl- +1.36 2 HNO 2 + 4 H+ + 4 e- N O + 3 H O

Calculating Cell Potential, E°cell for each _____ ___________ the ____________

_______________ is listed on the chart on p. 805 or the

reference sheet. the complete ______ is a combination of the

____________ and _____________ half reactions - the

_______ of the two is the _______ potential, _________ this is the usable energy given by:

______________________________________________ as all half reactions are listed as ____________ rxns, the

oxidation reaction ________ the sign, so:

______________________________________________

eg. Calculate the E° cell for the following unbalanced

equation:

Br2 + Cu 2 Br¯ + Cu+

Page 16: Oxidation Numbers, ox # - SCH4U1-CCVI - home + 3 e- Au +1.50 Ce4+ + e-1 Ce3+ +1.44 ClO4 1- + 8 H+ + 8 e- Cl1- + 4 H2O +1.39 Cl2 + 2 e- 2 Cl- +1.36 2 HNO 2 + 4 H+ + 4 e- N O + 3 H O

eg. a) Determine the anode, cathode and calculate the standard cell potential produced by a galvanic cell consisting of a Sn

electrode in contact with a solution of Sn2+ ions and a Cr

electrode in contact with a solution of Cr3+ ions.

b) Write the shorthand cell notation.

eg. Use complete half-reactions and potentials to predict whether the following reaction is spontaneous or non-spontaneous in aqueous solutions. If the cell is spontaneous, write the cell shorthand notation.

O2 + 2 SO

2 + 4 OH1- 2 SO

4

2- + 2 H2O

YOU MUST READ 9.6 Corrosion p.710 – 713 before the next lesson

Page 17: Oxidation Numbers, ox # - SCH4U1-CCVI - home + 3 e- Au +1.50 Ce4+ + e-1 Ce3+ +1.44 ClO4 1- + 8 H+ + 8 e- Cl1- + 4 H2O +1.39 Cl2 + 2 e- 2 Cl- +1.36 2 HNO 2 + 4 H+ + 4 e- N O + 3 H O

Reactions of Metals with Water The _______ is the _______ and will be ____________.

The ______ and ___________ in it will be the __________.

Need to consider:

i) __________ ________ - _____ of the 3

ii) ________________ _________ this requires a very long ____

_____, or an _______________, as O2 is not very water ________

iii) ________ ______________ - as with ______ ______

• Metals _______ the _____________ _______ _______ will be

________________

That’s why:

• Not ___ metals _______ with __________ ________

eg. ones that _____: ones that ______:

• Not ___ metals _______ with _____________ _______

eg. ones that _____: ones that ______:

• Not ___ metals _______ with _________ ________

eg. ones that _____: ones that ______:

Page 18: Oxidation Numbers, ox # - SCH4U1-CCVI - home + 3 e- Au +1.50 Ce4+ + e-1 Ce3+ +1.44 ClO4 1- + 8 H+ + 8 e- Cl1- + 4 H2O +1.39 Cl2 + 2 e- 2 Cl- +1.36 2 HNO 2 + 4 H+ + 4 e- N O + 3 H O

Metals with Metals • Alloys are _______ to change a metal’s ____________. • As _____ _______ undergo ____________ – rust,

corrosion, patina – _______ metals are _______ to stop

the ____________. eg. ___ or ___ need protection. • The ____________ metal, called a ___________ ______,

is ______ on the table _________ to the _______ in

_________. It will __________ the ____________ and

______ the _______.

eg. Which metals will ________ Zn?

eg. Which metals will ____ ________ Zn?

eg. a) Pick a metal that will protect Zn and determine the

cell potential if the cathode is oxygenated water.

b) Do the same for the case where Zn is not protected.

Page 19: Oxidation Numbers, ox # - SCH4U1-CCVI - home + 3 e- Au +1.50 Ce4+ + e-1 Ce3+ +1.44 ClO4 1- + 8 H+ + 8 e- Cl1- + 4 H2O +1.39 Cl2 + 2 e- 2 Cl- +1.36 2 HNO 2 + 4 H+ + 4 e- N O + 3 H O

Cells and Spontaneity

Reactants Products

ΔEcell Cell Type Spontaneity

Electrolytic cells, ΔE < 0

requires _____________ source of ______ to ________

the ____ __________ within the cell.

e- are __________ from the _________ and __________

to the ____________ by the ________________. rxn is then the _____________ of the ________________

rxn. used to __________________ and to produce _________

__________. Solution rxns so _____+ could be the ____________

and/or the ____________ reaction.

Page 20: Oxidation Numbers, ox # - SCH4U1-CCVI - home + 3 e- Au +1.50 Ce4+ + e-1 Ce3+ +1.44 ClO4 1- + 8 H+ + 8 e- Cl1- + 4 H2O +1.39 Cl2 + 2 e- 2 Cl- +1.36 2 HNO 2 + 4 H+ + 4 e- N O + 3 H O

eg. KI solution and battery

Cathode (red): Erº (V)

Anode (ox): Erº (V)

e- from the __________ (-ve) ____________ of the

_______________ reduce the ________

e- from the _____ flow to the ___________ (+ve) __________ of the ____________ to complete the _____________.

forms ______ and _______ from an ____________ sol’n!

Page 21: Oxidation Numbers, ox # - SCH4U1-CCVI - home + 3 e- Au +1.50 Ce4+ + e-1 Ce3+ +1.44 ClO4 1- + 8 H+ + 8 e- Cl1- + 4 H2O +1.39 Cl2 + 2 e- 2 Cl- +1.36 2 HNO 2 + 4 H+ + 4 e- N O + 3 H O

versus

Page 22: Oxidation Numbers, ox # - SCH4U1-CCVI - home + 3 e- Au +1.50 Ce4+ + e-1 Ce3+ +1.44 ClO4 1- + 8 H+ + 8 e- Cl1- + 4 H2O +1.39 Cl2 + 2 e- 2 Cl- +1.36 2 HNO 2 + 4 H+ + 4 e- N O + 3 H O

eg. Given the following molten system, AgCl, predict the products at each electrode. Assume inert electrodes and sufficient voltage to cause a reaction to take place. Consider all possible rxns.

eg. Given a 1.00 M solution of ZnI2 at 25°C, predict the anode and

cathode half cell reactions. What is the minimum voltage required for each cell to operate?

Page 23: Oxidation Numbers, ox # - SCH4U1-CCVI - home + 3 e- Au +1.50 Ce4+ + e-1 Ce3+ +1.44 ClO4 1- + 8 H+ + 8 e- Cl1- + 4 H2O +1.39 Cl2 + 2 e- 2 Cl- +1.36 2 HNO 2 + 4 H+ + 4 e- N O + 3 H O

Stoichiometry of Cell Reactions

Basic Concepts 1. q = It where:

q = _____________________

I = _____________________

t = _____________________

1C = _______________

2. Faraday’s Law: the ________ of a substance

__________ or ______________ is __________ related to the ____________ transferred

3. Faraday = ___________________________

F = ________________

4.

Page 24: Oxidation Numbers, ox # - SCH4U1-CCVI - home + 3 e- Au +1.50 Ce4+ + e-1 Ce3+ +1.44 ClO4 1- + 8 H+ + 8 e- Cl1- + 4 H2O +1.39 Cl2 + 2 e- 2 Cl- +1.36 2 HNO 2 + 4 H+ + 4 e- N O + 3 H O

eg.1 Calculate the amount of charge which passes

through an electrolytic cell with a current of 1.80A for 5.0 min.

eg. 2 Calculate the mass of Zn deposited by a

current of 2.50 A operating over 30.0 min in an electrolytic cell containing Zn(NO3)2(aq).

Page 25: Oxidation Numbers, ox # - SCH4U1-CCVI - home + 3 e- Au +1.50 Ce4+ + e-1 Ce3+ +1.44 ClO4 1- + 8 H+ + 8 e- Cl1- + 4 H2O +1.39 Cl2 + 2 e- 2 Cl- +1.36 2 HNO 2 + 4 H+ + 4 e- N O + 3 H O

Free Energy & Electrochemistry ΔGº = ___________ and ΔGº = __________ and… ΔGº = ______________

eg. Calculate ΔGº and Ke for the electrolytic Zn/Al

cell, Zn │ Al3+│Al.

Page 26: Oxidation Numbers, ox # - SCH4U1-CCVI - home + 3 e- Au +1.50 Ce4+ + e-1 Ce3+ +1.44 ClO4 1- + 8 H+ + 8 e- Cl1- + 4 H2O +1.39 Cl2 + 2 e- 2 Cl- +1.36 2 HNO 2 + 4 H+ + 4 e- N O + 3 H O

RT

0cell

EnF Keqln


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