Chapter 20: LEO the lion goes GER

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Chapter 20 LEO the lion goes GER

• OXIDATION AND REDUCTION REACTIONS

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RULES FOR ASSIGNING OXIDATION NUMBERS

• 1. EQUAL TO IONIC CHARGE
• EX NaCl Na1 Cl-1
• Except in H2O2 (H1 and O-1)
• 2. HYDROGEN IS ALWAYS 1
• 3. OXIDATION OF AN UNCOMBINED
• ELEMENT IS ALWAYS ZERO
• EX Mg Mg0

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RULES FOR ASSIGNING OXIDATION NUMBERS

• 4. SUM OF ALL OXIDATION S MUST
• EQUAL ZERO IN A COMPOUND
• EX NH3 N-3 H31
• FOR POLYATOMIC IONS, OXID.
• MUST THE CHARGE OF THE ION
• EX (SO4)-2 S6 O4-2
• (6) -8 -2

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LEO the lion

• Oxidation
• the combination of an element with oxygen (gain
  of oxygen).
• EX 4 Fe(s) 3O2(g) 2Fe2O3(s)
• Iron lost electrons oxidized
• EX Mg S MgS
• Substance that loses e-s is the
• Reducing Agent (reducing in size b/c of loss
  of electrons)

3 -2
0
0
2 -2
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Oxidized Reducing Agent

• The substance that is
• oxidized is the reducing agent
• Mg S MgS

Mg is OXIDIZED
0
2
Reducing Agent
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goes GER

• Reduction
• the loss of oxygen
• EX 2Fe2O3(s) 3C(s) 4Fe(s) 3CO2(g)
• Fe gains electrons reduced
• EX Mg S MgS
• Substance that accepts e-s is an
• Oxidizing Agent

4 -2
0
3 -2
0
2 -2
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Reduced Oxidizing Agent

• The substance that is
• reduced is the oxidizing agent
• Mg S MgS

S is REDUCED
0
-2
Oxidizing Agent