ib chemistry on redox, oxidation, reduction and oxidation number

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Prepared by Lawrence Kok

Video Tutorial on Redox, Oxidation, Reduction and oxidation number.

Video on Redox and Oxidation Number

Oxidation number acoss period

Redox reaction from Khan Academy

IB Chemistry Redox half reaction

Redox reaction from Khan academy

Oxidation calculation

Redox (Oxidation and Reduction)

Oxidation – Gain of oxygen ↑

Oxidation – Loss of hydrogen ↓ Reduction – Gain of hydrogen ↑

Reduction – Loss of oxygen ↓

Oxidation Number / State

• Arbitary /Imaginary charge assign to an element• Imagining electrons shared will move to a more electronegative atom

Oxidation Number / State

• Arbitary /Imaginary charge assign to an element• Imagining electrons shared will move to a more electronegative atom

Electron moving to CI Electron moving to C Electron moving to CI

Electron moving to O Electron moving to N Electron moving to O

• Oxidation number for oxygen is usually (-2) BUT will change if attached toa more electronegative atom like Fluorine

Oxidation Number / State

Oxidation number oxygen change from (-2) → (+2)

• Oxidation number for oxygen is usually (-2) BUT will change if attached toa more electronegative atom like Fluorine

• Oxidation number for Gp 7 (CI, Br, I) is usually (-1) BUT will change if attach toa more electronegative atom like oxygen

Oxidation Number / State

Oxidation number oxygen change from (-2) → (+2)

Oxidation number group 7 change from (-1) → (+1)

• Oxidation number for oxygen is usually (-2) BUT will change if attached toa more electronegative atom like Fluorine

• Oxidation number for Gp 7 (CI, Br, I) is usually (-1) BUT will change if attach toa more electronegative atom like oxygen

Oxidation Number / State

Oxidation number oxygen change from (-2) → (+2)

Oxidation number group 7 change from (-1) → (+1)

• Oxidation number for an atom or molecule of an element (NOT combined to formcompound) is always = ZERO (O)

Oxidation Number / State

• Oxidation number for Polyatomic Ions

Sum of oxidation number for polyatomic ion = Charge on the ion

Oxidation Number / State

• Oxidation number for Polyatomic Ions

Sum of oxidation number for polyatomic ion = Charge on the ion

• Sum of oxidation number of all atoms present is EQUAL to the CHARGE of ion

Oxidation Number / State• Oxidation number for monoatomic cations

MONOATOMIC ION -- Oxidation Number = Charge on ion

• Oxidation number for cation = Charge on ion

• Metal with more than > ONE oxidation number, Roman numeral is used

Oxidation Number / State

• Oxidation number for NON-METALS -- Electronegative → (-ve)

• Oxidation number for METALS -- Electropositive → (+ve)

Oxidation Number / State• Oxidation Number for Ionic Compound

Oxidation number S = +4 Oxidation number S = +6 Oxidation number N = +3 Oxidation number N = +5

Oxidation Number / State• Oxidation Number for Ionic Compound

Oxidation number S = +4 Oxidation number S = +6 Oxidation number N = +3 Oxidation number N = +5

Oxidation number Mn = +2 Oxidation number Mn = +4 Oxidation number S = +6 Oxidation number Mn = +7

Oxidation Number / State• Oxidation Number for Ionic Compound

Oxidation number S = +4 Oxidation number S = +6 Oxidation number N = +3 Oxidation number N = +5

Oxidation number Mn = +2 Oxidation number Mn = +4 Oxidation number S = +6 Oxidation number Mn = +7

Oxidation number Cr= +6 Oxidation number Cr = +6 Oxidation number N = +5 Oxidation number C = +4

Oxidation Number / StateExample: Determine the oxidation number for element below

1) V in V2O5

6) C in C2H3CI35) C in CH3CI4) O in F2O

3) O in CI2O2) Sn in SnCI4

Oxidation Number / StateExample: Determine the oxidation number for element below

1) V in V2O5

6) C in C2H3CI35) C in CH3CI4) O in F2O

3) O in CI2O2) Sn in SnCI4

Determine the oxidation number for the underlined elements

1) (SO4)2- 2) (SO3)2- 3) (OCI )- 1 4) (HCO3)-1

5) (MnO4)-1 7) H2 O 2

Oxidation Number / State

6) (F2O )

Determine the oxidation number for the underlined elements

1) (SO4)2- 2) (SO3)2- 3) (OCI )- 1 4) (HCO3)-1

5) (MnO4)-1 7) H2 O 2

Oxidation Number / State

Oxidation number for oxygen usually (-2) BUT (-1) in peroxide

6) (F2O )

Oxidation number for oxygen usually (-2) BUT (+2) if bond to more electronegative fluorine

• Charges on Anion and Polyatomic ion

Oxidation Number / State

• Charges on cations and oxidation number

Video on Redox and Oxidation Number

Oxidation number acoss period

Redox reaction from Khan Academy

IB Chemistry Redox half reaction

Redox reaction from Khan academy

Oxidation calculation

Acknowledgements

Thanks to source of pictures and video used in this presentation

Thanks to Creative Commons for excellent contribution on licenseshttp://creativecommons.org/licenses/

Prepared by Lawrence Kok

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