STEM Redox Reactions

Oxidation Numbers

100

CO₂

C = +4

O= -2

200

O₂

 O= 0

300

Al₂O₃

O= -2

Al = +3

400

K₂S

K = +1 

S = -2

500

Nitrate

NO₃^- 

O= -2

N= +5

Polyatomic ions

100

Sulfate oxidation numbers

O= -2

S = +6

200

Sodium and sulfate

Na₂SO₄

300

Barium and Phosphate

Ba₃(PO₄)₂

400

Aluminum  and Hydroxide

Al(OH)₃

500

Barium and carbonate

BaCO₃

Complete the half reaction

100

Cl^-1 → Cl

1 electron to product side

200

Hg⁺ → Hg

1 electrons to reactant side

300

Sn⁺⁴ → Sn ⁺²

 2 electrons to reactant side

400

Ni → Ni⁺²

2 electrons to product side

500

Br → Br^-1

1 electron to the reactant side

Create the half reaction

100

ZnCl₂ + Cu → CuCl₂ + Zn

Zn ⁺² + 2 e^-1 → Zn

Cu → Cu⁺² + 2 e^-1

200

2Mg + O₂ → 2MgO

Mg → Mg⁺² + 2 e^-1

O + 2 e^-1 → O

300

H₂ + F₂ → 2HF

H₂ → 2 H⁺ + 2 e^-

F₂ + 2e^-1  → 2F^-

400

Fe₂ O₃ + 3CO → 2Fe + 3CO₂

Fe ⁺³ + 3e^- → Fe

C⁺² →  C⁺⁴ + 2e^-1 

500

S + O₂ →  SO₂

S →  S⁺⁴ + 4e^-1 

O + 2e^-1 → O^-2

Create the complete equation

100

Li →  Li ⁺ + e^-1 

Zn ⁺² + 2e^- →  Zn

2 Li + Zn⁺² →  Zn + 2Li⁺

200

K →  K⁺¹ + e^-1

Cl₂ + 2 e^-1 →  2Cl^-1

2 K + Cl₂ →  2KCl

300

H₂ →  2 H⁺¹ + 2 e^-

O₂  + 4 e^-1→  2 O^-2

2H₂ + O₂ →  2H₂O

400

KMnO₄ Oxidation numbers

 K = 1

O= -2

Mn = 7

500

CaH₂ What are the oxidation numbers?

Ca + 2

H -1