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The Electrolytic Cell

The Electrolytic Cell. The Electrolytic Cell. In the electrolytic cell , a nonspontaneous redox reaction is forced to occur by the use of a source of electricity. In the electrolytic cell , electrons are FORCED to flow from the positive electrode to the negative electrode!

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The Electrolytic Cell

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  1. The Electrolytic Cell

  2. The Electrolytic Cell • In the electrolytic cell, a nonspontaneous redox reactionis forced to occur by the use of a source of electricity. • In the electrolytic cell, electrons are FORCED to flow from the positive electrode to the negative electrode! • In the electrolytic cell, the cathode has a negative charge and the anode has a positive charge!

  3. The Electrolytic Cell • Electrolytic cells are used to purify highly reactive elements from their compounds! • Na0 (sodium) never exists pure in nature! • Pure sodium can be extracted from NaCl by using an electrolytic cell.

  4. - + battery NaCl(l) The Electrolytic Cell e- Ex.1) • Electrons always flow out of the negative pole of an electric source such as a battery. • Electrons always flow towards the cathode. anode cathode Put a + on the positive electrode and a - on the negative electrode. - +

  5. - + battery NaCl(l) The Electrolytic Cell e- Ex.1) Write the reduction half reaction: ______________________ Write the oxidation half reaction: ______________________ anode cathode +1 -1 0 0 Na Cl2 2 Na1+ + 1 e- 2 → 2 Na0 2 Cl1- → Cl20 + 2 e-

  6. - + battery NaCl(l) The Electrolytic Cell e- Ex.1) _______________________________ [write the balanced redox reaction] anode cathode +1 -1 0 0 Na Cl2 2 Na1+ + 2 Cl1- → 2 Na0 + Cl20

  7. - + battery NaCl(l) The Electrolytic Cell e- Ex.1) a) The electrode on the left is the ____ode and the electrode on the right is the ____ode. +1 -1 0 0 Na Cl2 an cath

  8. - + battery NaCl(l) The Electrolytic Cell e- Ex.1) b) The positive electrode is on the __________ and the negative electrode is on the __________. +1 -1 0 0 Na Cl2 left right

  9. - + battery NaCl(l) The Electrolytic Cell e- Ex.1) c) Write the half reaction that occurs at the electrode on the left. +1 -1 0 0 Na Cl2 2 Cl1- → Cl20 + 2 e- _________________________________________

  10. - + battery NaCl(l) The Electrolytic Cell e- Ex.1) d) Write the half reaction that occurs at the electrode on the right. +1 -1 0 0 Na Cl2 Na1+ + 1 e- → Na0 _________________________________________

  11. - + battery KBr(l) The Electrolytic Cell e- Ex.2) • Electrons always flow out of the negative pole of an electric source such as a battery. • Electrons always flow towards the cathode. cathode anode Put a + on the positive electrode and a - on the negative electrode. - +

  12. battery The Electrolytic Cell e- - Ex.2) Write the reduction half reaction: ______________________ Write the oxidation half reaction: ______________________ + cathode anode +1 -1 KBr(l) 0 0 K Br2 2 K1+ + 1 e- 2 → 2 K0 2 Br1- → Br20 + 2 e-

  13. battery The Electrolytic Cell e- - Ex.2) _______________________________ [write the balanced redox reaction] + cathode anode +1 -1 KBr(l) 0 0 K Br2 2 K1+ + 2 Br1- → 2 K0 + Br20

  14. battery The Electrolytic Cell - Ex.2) a) The electrode on the left is the ____ode and the electrode on the right is the ____ode. + +1 -1 KBr(l) 0 0 K Br2 cath an

  15. battery The Electrolytic Cell e- - Ex.2) b) The positive electrode is on the __________ and the negative electrode is on the __________. + +1 -1 KBr(l) 0 0 K Br2 right left

  16. The Electrolytic Cell e- - Ex.2) c) Write the half reaction that occurs at the electrode on the left. + battery +1 -1 KBr(l) 0 0 K Br2 K1+ + 1 e- → K0 _________________________________________

  17. battery The Electrolytic Cell e- - Ex.2) d) Write the half reaction that occurs at the electrode on the right. + +1 -1 KBr(l) 0 0 K Br2 2 Br1- → Br20 + 2 e- _________________________________________

  18. The Electrolytic Cell e- - Ex.3) • Electrons always flow out of the negative pole of an electric source such as a battery. • Electrons always flow towards the cathode. + battery cathode anode Put a + on the positive electrode and a - on the negative electrode. - + H2O(l)

  19. battery The Electrolytic Cell e- - Ex.3) _______________________________ [write the balanced redox reaction] + cathode anode +1 -2 H2O(l) 0 0 H2 O2 2 H2O → 2 H20 + O20

  20. battery The Electrolytic Cell - Ex.3) a) The electrode on the left is the ____ode and the electrode on the right is the ____ode. + +1 -2 H2O(l) 0 0 H2 O2 cath an

  21. battery The Electrolytic Cell e- - Ex.3) b) The positive electrode is on the __________ and the negative electrode is on the __________. + +1 -2 H2O(l) 0 0 H2 O2 right left

  22. The Electrolytic Cell e- - Ex.3) c) What substance is produced at the electrode on the left? ____________________ + battery +1 -2 H2O(l) 0 0 H2 O2 Hydrogen gas

  23. The Electrolytic Cell e- - Ex.3) d) What substance is produced at the electrode on the right? ____________________ + battery +1 -2 H2O(l) 0 0 H2 O2 Oxygen gas

  24. The Electrolytic Cell e- - Ex.3) e) Why must a small amount of electrolyte (such as an acid) be added to the water in order for the electrolytic decomposition to work?________________________ ___________________________________________ + battery +1 -2 H2O(l) 0 0 H2 O2 because pure water does not conduct electricity, so an electrolyte is added.

  25. The Electrolytic Cell Ex. (4) Which half-reaction correctly represents the reduction of a potassium ion? (1) K+ + e- → K (3) K+ → K + e- (2) K + e- → K+ (4) K → K+ + e- Ex. (5) Given the equation: 2 Al + 3 Cu2+ → 2 Al3+ + 3 Cu The oxidation half-reaction is (1) Al → Al3+ + 3e- (3) Al + 3e- → Al3+ (2) Cu2+ + 2e- → Cu (4) Cu2+ → Cu + 2e-

  26. The Electrolytic Cell Ex. (6) During the electrolysis of molten cesium chloride (CsCl), pure cesium is produced at the (1) positively charged cathode and pure chloride gas is produced at the negatively charged anode (2) negatively charged cathode and pure chloride gas is produced at the positively charged anode (3) positively charged anode and pure chloride gas is produced at the negatively charged cathode (4) negatively charged anode and pure chloride gas is produced at the positively charged cathode

  27. The Electrolytic Cell Ex. (7) Given the voltaic cell: Pb(s) + Cu2+(aq) → Pb2+(aq) + Cu(s) The electrons will flow from (1) the Pb(s) electrode to the Cu(s) electrode (2) the Cu(s) electrode to the Pb(s) electrode (3) the Pb2+(aq) electrode to the Cu(s) electrode (4) the Cu2+(aq) electrode to the Pb(s) electrode Ex. (8) What is conserved during all chemical reactions? (1) mass, only (3) both mass and charge (2) charge, only (4) neither mass nor charge

  28. The Electrolytic Cell e- e- Anode + Battery - Cathode - Na0 + Na0 Na0 Na0 Na0 Na+ Cl- Cl- Na+ Na0 Na0 Na+ Na0 Na0 Na0 Na0 Na0 Cl- Cl20 Na0 Na0 Na0 Cl- Na0 Na0 Na+ Na0 Na+ Na0 Molten Na(ℓ) Molten NaCl(ℓ) Cl- Na0 2 NaCl  2 Na + Cl2 Reduction: 2 Na+1 + 2e-  2 Na0 Oxidation: 2 Cl-1  Cl20 + 2 e-

  29. The Electrolytic Cell e- e- Anode + Battery - Cathode - + Br- H2O Br- Br- Cu+2 H2O Cu+2 H2O H2O Br- Br20 H2O Cu0 Br- Br- Cu+2 aqueous CuBr2(aq) H2O CuBr2 Cu + Br2 Reduction: Cu+2 + 2e-  Cu0 Oxidation: 2 Br-1  Br20+ 2 e-

  30. The Electrolytic Cell e- e- - Battery + Anode Cathode - + H2O H2O H2O H2O H2O H2O H+1 H+1 H20 H20 O20 O-2 H2O H+1 H2O H+1 O-2 H2O H2O(ℓ) H2O 2 H2O 2 H2 + O2 Reduction: 4 H+1 + 4e-  2 H20 Oxidation: 2 O-2  O20+ 4 e-

  31. The Electrolytic Cell

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