the breathalyser reaction c 2 h 2 oh+ cr 2 o 7 2- → ch 3 cooh+cr 3+
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The Breathalyser Reaction
C2H2OH + Cr2O7
2- → CH3COOH + Cr3+
Ethanol Orange Acetic Acid Green If the orange colour decreases there is alcohol present. It is measured with a spectrophotometer. The more it decreases, the higher the blood alcohol content. Legal Limit Class 5 Licence 0.08 mg/mLLegal Limit New Driver 0.00 mg/mL Substance OxidizedSubstance ReducedReducing AgentOxidizing Agent
The Breathalyser ReactionLook at the oxidation numbers!-0.5 +6 0 +3
C2H2OH + Cr2O72- → CH3COOH + Cr3+
Ethanol Orange Acetic Acid Green If the orange colour decreases there is alcohol present. It is measured with a spectrophotometer. The more it decreases, the higher the blood alcohol content. Legal Limit Class 5 Licence 0.08 mg/mLLegal Limit New Driver 0.00 mg/mL Substance OxidizedSubstance ReducedReducing AgentOxidizing Agent
The Breathalyser ReactionLook at the oxidation numbers!-0.5 +6 0 +3
C2H2OH + Cr2O72- → CH3COOH + Cr3+
Ethanol Orange Acetic Acid Green If the orange colour decreases there is alcohol present. It is measured with a spectrophotometer. The more it decreases, the higher the blood alcohol content. Legal Limit Class 5 Licence 0.08 mg/mLLegal Limit New Driver 0.00 mg/mL Substance Oxidized C2H2OH Substance ReducedReducing AgentOxidizing Agent
The Breathalyser ReactionLook at the oxidation numbers!-0.5 +6 0 +3
C2H2OH + Cr2O72- → CH3COOH + Cr3+
Ethanol Orange Acetic Acid Green If the orange colour decreases there is alcohol present. It is measured with a spectrophotometer. The more it decreases, the higher the blood alcohol content. Legal Limit Class 5 Licence 0.08 mg/mLLegal Limit New Driver 0.00 mg/mL Substance Oxidized C2H2OH Substance ReducedReducing Agent C2H2OH Oxidizing Agent
The Breathalyser ReactionLook at the oxidation numbers!-0.5 +6 0 +3
C2H2OH + Cr2O72- → CH3COOH + Cr3+
Ethanol Orange Acetic Acid Green If the orange colour decreases there is alcohol present. It is measured with a spectrophotometer. The more it decreases, the higher the blood alcohol content. Legal Limit Class 5 Licence 0.08 mg/mLLegal Limit New Driver 0.00 mg/mL Substance Oxidized C2H2OH Substance Reduced Cr2O7
2-
Reducing Agent C2H2OH Oxidizing Agent
The Breathalyser ReactionLook at the oxidation numbers!-0.5 +6 0 +3
C2H2OH + Cr2O72- → CH3COOH + Cr3+
Ethanol Orange Acetic Acid Green If the orange colour decreases there is alcohol present. It is measured with a spectrophotometer. The more it decreases, the higher the blood alcohol content. Legal Limit Class 5 Licence 0.08 mg/mLLegal Limit New Driver 0.00 mg/mL Substance Oxidized C2H2OH Substance Reduced Cr2O7
2-
Reducing Agent C2H2OH Oxidizing Agent Cr2O7
2-
Balance in acid solution
C2H2OH + Cr2O7
2- → CH3COOH + Cr3+
Balance in acid solution
C2H2OH + Cr2O7
2- → CH3COOH + Cr3+
Cr2O72- → Cr3+
C2H2OH → CH3COOH
Balance in acid solution
C2H2OH + Cr2O7
2- → CH3COOH + Cr3+
Cr2O72- → 2Cr3+
C2H2OH → CH3COOH
Balance in acid solution
C2H2OH + Cr2O7
2- → CH3COOH + Cr3+
Cr2O72- → 2Cr3+ + 7H2O
C2H2OH + H2O → CH3COOH
Balance in acid solution
C2H2OH + Cr2O7
2- → CH3COOH + Cr3+
14H+ + Cr2O72- + → 2Cr3+ + 7H2O
C2H2OH + H2O → CH3COOH + H+
Balance in acid solution
C2H2OH + Cr2O7
2- → CH3COOH + Cr3+
14H+ + Cr2O72- + 6e- → 2Cr3+ + 7H2O
C2H2OH + H2O → CH3COOH + H+ + 1e-
Balance in acid solution
C2H2OH + Cr2O7
2- → CH3COOH + Cr3+
14H+ + Cr2O72- + 6e- → 2Cr3+ + 7H2O
6(C2H2OH + H2O→ CH3COOH+ H+ + 1e-)
Balance in acid solution
C2H2OH + Cr2O7
2- → CH3COOH + Cr3+
14H+ + Cr2O72- + 6e- → 2Cr3+ + 7H2O
6(C2H2OH + H2O→ CH3COOH+ H+ + 1e-)
14H+ + Cr2O72- + 6C2H2OH + 6H2O → 2Cr3++7H2O+6CH3COOH+6H+
Balance in acid solution
C2H2OH + Cr2O7
2- → CH3COOH + Cr3+
14H+ + Cr2O72- + 6e- → 2Cr3+ + 7H2O
6(C2H2OH + H2O→ CH3COOH+ H+ + 1e-)
8 114H+ + Cr2O7
2- + 6C2H2OH + 6H2O → 2Cr3++7H2O+6CH3COOH+6H+
Balance in acid solution
C2H2OH + Cr2O7
2- → CH3COOH + Cr3+
14H+ + Cr2O72- + 6e- → 2Cr3+ + 7H2O
6(C2H2OH + H2O→ CH3COOH+ H+ + 1e-)
8H+ + Cr2O72- + 6C2H2OH → 2Cr3+ + 1H2O + 6CH3COOH
Balance in acid solution
C2H2OH + Cr2O7
2- → CH3COOH + Cr3+
14H+ + Cr2O72- + 6e- → 2Cr3+ + 7H2O
6(C2H2OH + H2O→ CH3COOH+ H+ + 1e-)
8H+ + Cr2O72- + 6C2H2OH → 2Cr3+ + 1H2O + 6CH3COOH
+6 +6
Balance in base solution
8H+ + Cr2O72- + 6C2H2OH → 2Cr3+ + 1H2O + 6CH3COOH
Balance in base solution
8H+ + Cr2O72- + 6C2H2OH → 2Cr3+ + 1H2O + 6CH3COOH
8OH- 8OH-
Balance in base solution
8H+ + Cr2O72- + 6C2H2OH → 2Cr3+ + 1H2O + 6CH3COOH
8OH- 8H2O 8OH-
Balance in base solution
8H+ + Cr2O72- + 6C2H2OH → 2Cr3+ + 1H2O + 6CH3COOH
8OH- 8H2O 8OH-
Balance in base solution
Cr2O72- + 6C2H2OH → 2Cr3 + 1H2O + 6CH3COOH + 8OH-
7 8H2O
Balance in base solution
7H2O + Cr2O72- + 6C2H2OH → 2Cr3+ + 6CH3COOH + 8OH-
Review of Cells
Electrochemical Electrolytic Is a power supply Requires power supplySpontaneous (+ ve) Nonspontaneous(-ve)Makes electricity Makes chemicals Reduction is highest on Chart Reduction is the –ve
For all cells:
Cations migrate to the cathode, which is the site of reduction. Anions migrate to the anode, which is the site of oxidation. Electrons travel through the wire from anode to cathode.
Complete the Chart Electrochemical Cell: Zn, Zn(NO3)2 II Cu, CuSO4
Anode: Reaction:
Cathode: Reaction:
E0 =
Complete the Chart Electrochemical Cell: Zn, Zn(NO3)2 II Cu, CuSO4
Anode: Zn Reaction:
Cathode: Cu Reaction:
E0 =
Higher on reduction Chart
Complete the Chart Electrochemical Cell: Zn, Zn(NO3)2 II Cu, CuSO4
Anode: Zn Reaction: Zn → Zn2+ + 2e- 0.76 v
Cathode: Cu Reaction:
E0 =
Higher on reduction Chart
Complete the Chart Electrochemical Cell: Zn, Zn(NO3)2 II Cu, CuSO4
Anode: Zn Reaction: Zn(s) → Zn2+ + 2e- 0.76 v
Cathode: Cu Reaction: Cu2+ + 2e- → Cu(s) 0.34 v
E0 = Higher on reduction Chart
Complete the Chart Electrochemical Cell: Zn, Zn(NO3)2 II Cu, CuSO4
Anode: Zn Reaction: Zn → Zn2+ + 2e- 0.76 v
Cathode: Cu Reaction: Cu2+ + 2e- → Cu(s) 0.34 v
E0 = 1.10 v Higher on reduction Chart
Electrolytic Cell: Molten AlCl3
Anode: Reaction: Cathode: Reaction:
Electrolytic Cell: Molten AlCl3 Al3+ Cl-
Anode: C Reaction: Cathode: C Reaction:
Electrolytic Cell: Molten AlCl3 Al3+ Cl-
Anode: C Reaction: Cathode: C Reaction:
Put the vowels together: AnodeAnionOxidation
Electrolytic Cell: Molten AlCl3 Al3+ Cl-
Anode: C Reaction: 2Cl- → Cl2 + 2e- -1.36 v Cathode: C Reaction:
Put the vowels together: AnodeAnionOxidation
Oxidation of Anion
Electrolytic Cell: Molten AlCl3
Anode: C Reaction: 2Cl- → Cl2 + 2e- -1.36 v Cathode: C Reaction:
Put the consonants together: CathodeCationReduction
Electrolytic Cell: Molten AlCl3
Anode: C Reaction: 2Cl- → Cl2 + 2e- -1.36 v Cathode: C Reaction: Al3+ + 3e- → Al -1.66 v
Put the consonants together: CathodeCationReduction
Reduction of Cation
Electrolytic Cell: Molten AlCl3
Anode: C Reaction: 2Cl- → Cl2 + 2e- -1.36 v Cathode: C Reaction: Al3+ + 3e- → Al -1.66 v E0 = -3.02 v
Electrolytic Cell: Molten AlCl3
Anode: C Reaction: 2Cl- → Cl2 + 2e- -1.36 v Cathode: C Reaction: Al3+ + 3e- → Al -1.66 v E0 = -3.02 v MTV = +3.02 v
Electrolytic Cell: KBr(aq)
Anode: Cathode:
Electrolytic Cell: KBr(aq) K+ Br- H2O
Anode: C Cathode: C
Electrolytic Cell: KBr(aq) K+ Br- H2O
Anode: C Cathode: C
Put the vowels together: AnodeAnion or waterOxidation
Electrolytic Cell: KBr(aq)
Anode: C 2Br- → Br2 + 2e- -1.09 v Cathode: C
Oxidation of Anion or WaterTake Lower one!
Electrolytic Cell: KBr(aq)
Anode: C 2Br- → Br2 + 2e- -1.09 v Cathode: C
Put the consonants together: CathodeCation or waterReduction
Oxidation of Anion or WaterTake Lower one!
Electrolytic Cell: KBr(aq)
Anode: C 2Br- → Br2 + 2e- -1.09 v Cathode: C 2H2O + 2e- → H2 + 2OH- -0.41 v
Put the consonants together: CathodeCation or waterReduction
Oxidation of Anion or WaterTake Lower one!
Reduction of Cation or WaterTake Higher one!
Electrolytic Cell: KBr(aq)
Anode: C 2Br- → Br2 + 2e- -1.09 v Cathode: C 2H2O + 2e- → H2 + 2OH- -0.41 v E0 = -1.50 v
Oxidation of Anion or WaterTake Lower one!
Reduction of Cation or WaterTake Higher one!
Electrolytic Cell: KBr(aq)
Anode: C 2Br- → Br2 + 2e- -1.09 v Cathode: C 2H2O + 2e- → H2 + 2OH- -0.41 v E0 = -1.50 v MTV = +1.50 v
Oxidation of Anion or WaterTake Lower one!
Reduction of Cation or WaterTake Higher one!
Electrochemical Cell: Ag, AgNO3 II Sn, Sn(NO3)2
Cathode: Anode:
Electrochemical Cell: Ag, AgNO3 II Sn, Sn(NO3)2
*higher
Cathode: Ag Anode:
Electrochemical Cell: Ag, AgNO3 II Sn, Sn(NO3)2
*higher
Cathode: Ag Ag+ + e- → Ag(s) +0.80 v Anode:
Electrochemical Cell: Ag, AgNO3 II Sn, Sn(NO3)2
*higher
Cathode: Ag Ag+ + e- → Ag(s) +0.80 v Anode: Sn
Electrochemical Cell: Ag, AgNO3 II Sn, Sn(NO3)2
*higher
Cathode: Ag Ag+ + e- → Ag(s) +0.80 v Anode: Sn Sn → Sn2+ + 2e- +0.14 v
Electrochemical Cell: Ag, AgNO3 II Sn, Sn(NO3)2
*higher
Cathode: Ag 2(Ag+ + e- → Ag(s)) +0.80 v Anode: Sn Sn → Sn2+ + 2e- +0.14 v 2Ag+ + Sn → Sn2+ + 2Ag(s) E0 = 0.94 v
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