1. The Breathalyser Reaction
C2H2OH Cr2O → 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 mg/mL
Legal Limit New Driver mg/mL
Substance Oxidized
Substance Reduced
Reducing Agent
Oxidizing Agent

2. The Breathalyser Reaction
Look at the oxidation numbers!
-0.5  
C2H2OH Cr2O → 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 mg/mL
Legal Limit New Driver mg/mL
Substance Oxidized
Substance Reduced
Reducing Agent
Oxidizing Agent

3. The Breathalyser Reaction
Look at the oxidation numbers!
-0.5  
C2H2OH Cr2O → 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 mg/mL
Legal Limit New Driver mg/mL
Substance Oxidized C2H2OH
Substance Reduced
Reducing Agent
Oxidizing Agent

4. The Breathalyser Reaction
Look at the oxidation numbers!
-0.5  
C2H2OH Cr2O → 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 mg/mL
Legal Limit New Driver mg/mL
Substance Oxidized C2H2OH
Substance Reduced
Reducing Agent C2H2OH
Oxidizing Agent

5. The Breathalyser Reaction
Look at the oxidation numbers!
-0.5  
C2H2OH Cr2O → 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 mg/mL
Legal Limit New Driver mg/mL
Substance Oxidized C2H2OH
Substance Reduced Cr2O72-
Reducing Agent C2H2OH
Oxidizing Agent  

6. The Breathalyser Reaction
Look at the oxidation numbers!
-0.5  
C2H2OH Cr2O → 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 mg/mL
Legal Limit New Driver mg/mL
Substance Oxidized C2H2OH
Substance Reduced Cr2O72-
Reducing Agent C2H2OH
Oxidizing Agent Cr2O72-  

7. Balance in acid solution
C2H2OH Cr2O → CH3COOH + Cr3+

8. Balance in acid solution
C2H2OH Cr2O → CH3COOH + Cr3+
Cr2O → Cr3+
C2H2OH → CH3COOH

9. Balance in acid solution
C2H2OH Cr2O → CH3COOH + Cr3+
Cr2O → 2Cr3+
C2H2OH → CH3COOH

10. Balance in acid solution
C2H2OH Cr2O → CH3COOH + Cr3+
Cr2O72- → 2Cr H2O
C2H2OH H2O → CH3COOH

11. Balance in acid solution
C2H2OH Cr2O → CH3COOH + Cr3+
14H+ + Cr2O → 2Cr H2O
C2H2OH H2O → CH3COOH + H+

12. Balance in acid solution
C2H2OH Cr2O → CH3COOH + Cr3+
14H+ + Cr2O e- → 2Cr H2O
C2H2OH H2O → CH3COOH + H+ + 1e-

13. Balance in acid solution
C2H2OH Cr2O → CH3COOH + Cr3+
14H+ + Cr2O e- → 2Cr H2O
6(C2H2OH H2O → CH3COOH+ H+ + 1e-)

14. Balance in acid solution
C2H2OH Cr2O → CH3COOH + Cr3+
14H+ + Cr2O e- → 2Cr H2O
6(C2H2OH H2O → CH3COOH+ H+ + 1e-)
14H+ + Cr2O C2H2OH + 6H2O → 2Cr3++7H2O+6CH3COOH+6H+

15. Balance in acid solution
C2H2OH Cr2O → CH3COOH + Cr3+
14H+ + Cr2O e- → 2Cr H2O
6(C2H2OH H2O → CH3COOH+ H+ + 1e-)
14H+ + Cr2O C2H2OH + 6H2O → 2Cr3++7H2O+6CH3COOH+6H+

16. Balance in acid solution
C2H2OH Cr2O → CH3COOH + Cr3+
14H+ + Cr2O e- → 2Cr H2O
6(C2H2OH H2O → CH3COOH+ H+ + 1e-)
8H+ + Cr2O C2H2OH → 2Cr H2O CH3COOH

17. Balance in acid solution
C2H2OH Cr2O → CH3COOH + Cr3+
14H+ + Cr2O e- → 2Cr H2O
6(C2H2OH H2O → CH3COOH+ H+ + 1e-)
8H+ + Cr2O C2H2OH → 2Cr H2O CH3COOH

18. Balance in base solution
8H+ + Cr2O C2H2OH → 2Cr H2O CH3COOH

19. Balance in base solution
8H+ + Cr2O C2H2OH → 2Cr H2O CH3COOH
8OH OH-

20. Balance in base solution
8H+ + Cr2O C2H2OH → 2Cr H2O CH3COOH
8OH- 8H2O 8OH-

21. Balance in base solution
8H+ + Cr2O C2H2OH → 2Cr H2O CH3COOH
8OH- 8H2O 8OH-

22. Balance in base solution
Cr2O C2H2OH → 2Cr H2O CH3COOH + 8OH- 7
8H2O

23. Balance in base solution
7H2O + Cr2O C2H2OH → 2Cr CH3COOH + 8OH-

24. Review of Cells
Electrochemical Electrolytic
Is a power supply Requires power supply
Spontaneous (+ ve) Nonspontaneous(-ve)
Makes electricity Makes chemicals
Reduction is highest on Chart Reduction is the –ve

25. 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.

26. Electrochemical Cell: Zn, Zn(NO3)2 II Cu, CuSO4
Complete the Chart
Electrochemical Cell: Zn, Zn(NO3)2 II Cu, CuSO4
Anode: Reaction:
Cathode: Reaction:
E0 =

27. Electrochemical Cell: Zn, Zn(NO3)2 II Cu, CuSO4
Complete the Chart
Electrochemical Cell: Zn, Zn(NO3)2 II Cu, CuSO4
Anode: Zn Reaction:
Cathode: Cu Reaction:
E0 =
Higher on reduction Chart

28. Electrochemical Cell: Zn, Zn(NO3)2 II Cu, CuSO4
Complete the Chart
Electrochemical Cell: Zn, Zn(NO3)2 II Cu, CuSO4
Anode: Zn Reaction: Zn → Zn2+ + 2e v
Cathode: Cu Reaction:
E0 =
Higher on reduction Chart

29. Electrochemical Cell: Zn, Zn(NO3)2 II Cu, CuSO4
Complete the Chart
Electrochemical Cell: Zn, Zn(NO3)2 II Cu, CuSO4
Anode: Zn Reaction: Zn(s) → Zn2+ + 2e v
Cathode: Cu Reaction: Cu e- → Cu(s) v
E0 =
Higher on reduction Chart

30. Electrochemical Cell: Zn, Zn(NO3)2 II Cu, CuSO4
Complete the Chart
Electrochemical Cell: Zn, Zn(NO3)2 II Cu, CuSO4
Anode: Zn Reaction: Zn → Zn2+ + 2e v
Cathode: Cu Reaction: Cu e- → Cu(s) v
E0 = 1.10 v
Higher on reduction Chart

31. Electrolytic Cell: Molten AlCl3 Anode: Reaction: Cathode: Reaction:
Electrolytic Cell: Molten AlCl3
Anode: Reaction:
Cathode: Reaction:

32. Electrolytic Cell: Molten AlCl3 Al3+ Cl- Anode: C Reaction:
Electrolytic Cell: Molten AlCl3 Al3+ Cl-
Anode: C Reaction:
Cathode: C Reaction:

33. Electrolytic Cell: Molten AlCl3 Al3+ Cl- Anode: C Reaction:
Electrolytic Cell: Molten AlCl3 Al3+ Cl-
Anode: C Reaction:
Cathode: C Reaction:
Put the vowels together:
Anode
Anion
Oxidation

34. Electrolytic Cell: Molten AlCl3 Al3+ Cl-
Electrolytic Cell: Molten AlCl3 Al3+ Cl-
Anode: C Reaction: 2Cl- → Cl e v
Cathode: C Reaction:
Put the vowels together:
Anode
Anion
Oxidation
Oxidation of Anion

35. Electrolytic Cell: Molten AlCl3
Electrolytic Cell: Molten AlCl3
Anode: C Reaction: 2Cl- → Cl e v
Cathode: C Reaction:
Put the consonants together:
Cathode
Cation
Reduction

36. Electrolytic Cell: Molten AlCl3
Electrolytic Cell: Molten AlCl3
Anode: C Reaction: 2Cl- → Cl e v
Cathode: C Reaction: Al e- → Al v
Put the consonants together:
Cathode
Cation
Reduction
Reduction of Cation

37. Electrolytic Cell: Molten AlCl3
Electrolytic Cell: Molten AlCl3
Anode: C Reaction: 2Cl- → Cl e v
Cathode: C Reaction: Al e- → Al v
E0 = v

38. Electrolytic Cell: Molten AlCl3
Electrolytic Cell: Molten AlCl3
Anode: C Reaction: 2Cl- → Cl e v
Cathode: C Reaction: Al e- → Al v
E0 = v
MTV = v

39.  Electrolytic Cell: KBr(aq)
Anode:
Cathode:

40.  Electrolytic Cell: KBr(aq) K+ Br- H2O
Anode: C
Cathode: C

41. Anode Anion or water Oxidation Anode: C Cathode: C
 Electrolytic Cell: KBr(aq) K+ Br H2O
Anode: C
Cathode: C
 Put the vowels together:
Anode
Anion or water
Oxidation

42. Oxidation of Anion or Water Take Lower one!
 Electrolytic Cell: KBr(aq)
Anode: C 2Br- → Br e v
Cathode: C
Oxidation of Anion or Water
Take Lower one!

43. Put the consonants together: Cathode Cation or water Reduction
 Electrolytic Cell: KBr(aq)
Anode: C 2Br- → Br e v
Cathode: C
Put the consonants together:
Cathode
Cation or water
Reduction
Oxidation of Anion or Water
Take Lower one!

44. Put the consonants together: Cathode Cation or water Reduction
 Electrolytic Cell: KBr(aq)
Anode: C 2Br- → Br e v
Cathode: C 2H2O + 2e- → H2 + 2OH v
Put the consonants together:
Cathode
Cation or water
Reduction
Oxidation of Anion or Water
Take Lower one!
Reduction of Cation or Water
Take Higher one!

45. E0 = -1.50 v Oxidation of Anion or Water Take Lower one!
 Electrolytic Cell: KBr(aq)
Anode: C 2Br- → Br e v
Cathode: C 2H2O + 2e- → H2 + 2OH v
E0 = v
Oxidation of Anion or Water
Take Lower one!
Reduction of Cation or Water
Take Higher one!

46. E0 = -1.50 v MTV = +1.50 v Oxidation of Anion or Water Take Lower one!
 Electrolytic Cell: KBr(aq)
Anode: C 2Br- → Br e v
Cathode: C 2H2O + 2e- → H2 + 2OH v
E0 = v
MTV = v
Oxidation of Anion or Water
Take Lower one!
Reduction of Cation or Water
Take Higher one!

47. Electrochemical Cell: Ag, AgNO3 II Sn, Sn(NO3)2
Electrochemical Cell: Ag, AgNO3 II Sn, Sn(NO3)2
Cathode:
Anode:

48. Electrochemical Cell: Ag, AgNO3 II Sn, Sn(NO3)2 *higher Cathode: Ag
Electrochemical Cell: Ag, AgNO3 II Sn, Sn(NO3)2
*higher
Cathode: Ag
Anode:

49. Electrochemical Cell: Ag, AgNO3 II Sn, Sn(NO3)2 *higher
Electrochemical Cell: Ag, AgNO3 II Sn, Sn(NO3)2
*higher
Cathode: Ag Ag e- → Ag(s) v
Anode:

50. Electrochemical Cell: Ag, AgNO3 II Sn, Sn(NO3)2 *higher
Electrochemical Cell: Ag, AgNO3 II Sn, Sn(NO3)2
*higher
Cathode: Ag Ag e- → Ag(s) v
Anode: Sn

51. Electrochemical Cell: Ag, AgNO3 II Sn, Sn(NO3)2 *higher
Electrochemical Cell: Ag, AgNO3 II Sn, Sn(NO3)2
*higher
Cathode: Ag Ag e- → Ag(s) v
Anode: Sn Sn → Sn e v

52. Electrochemical Cell: Ag, AgNO3 II Sn, Sn(NO3)2 *higher
Electrochemical Cell: Ag, AgNO3 II Sn, Sn(NO3)2
*higher
Cathode: Ag 2(Ag e- → Ag(s)) v
Anode: Sn Sn → Sn e v
2Ag+ + Sn → Sn Ag(s) E0 = 0.94 v