11 REDOX Challenge REDOX Challenge ContestContest

Florida State College @ JacksonvilleFlorida State College @ Jacksonville

North CampusNorth Campus

Presenters:Presenters:

Dr. Joseph LangatDr. Joseph Langat

Dr. Kathleen LaurenzoDr. Kathleen Laurenzo

Professor John TaylorProfessor John Taylor

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AbstractAbstract• 2YC3 1932YC3 193rdrd Conference Abstract: Conference Abstract: The presenters conduct each term in all CHM 1025C

(introductory), CHM 2045C (gen chem I), and CHM 2046C (gen chem II) chemistry courses the REDOX Challenge Contest at North Campus of Florida State College @ Jacksonville. This is a collaborative paper and pencil laboratory exercise, which in three hours transforms a novice into an advance student at balancing REDOX equations. The Student works in teams of two with an option to have an outside expert to join their team and participate to challenge and beat Professor Taylor at REDOX balancing. Conference participants will be given a CD with all the files used in the contest. Dr. Langat and Dr. Laurenzo act as roving experts to help struggling student teams. All three attempt to attend every lab session when there is not class conflict during ‘REDOX’ week in each particular course...

Web Site: Web Site: http://www.fccj.us/REDOX/REDOXstudy.html

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55If Not Ion Exchange then the reaction is REDOX?

66Pot Luck Lunch or Dinner Faculty Provide two, three or four pizzas as main course!Faculty Provide two, three or four pizzas as main course!This gives a relaxed atmosphere and helps student bonding!

Faculty Provide two, three or four pizzas as main course!Faculty Provide two, three or four pizzas as main course!This gives a relaxed atmosphere and helps student bonding!

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Three Divisions: Three Divisions: The Novice Division:The Novice Division:

CHM 1020/CHM 1025C/CHM 1032C

Students are beginners: • 12 Rounds• Mostly Net Ionic Equations• At least four Acid Media Equations• At least Four Basic media Equations• Student Choice usually existing equations• Pre/Post Lab Homework – 20 equations• Rounds 1-8: five different equations distributed

CHM 1020/CHM 1025C/CHM 1032C

Students are beginners: • 12 Rounds• Mostly Net Ionic Equations• At least four Acid Media Equations• At least Four Basic media Equations• Student Choice usually existing equations• Pre/Post Lab Homework – 20 equations• Rounds 1-8: five different equations distributed

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Three Divisions: Three Divisions: The Intermediate The Intermediate

Division:Division:

CHM 2045C StudentsCHM 2045C Students

Students have REDOX each semester:Students have REDOX each semester: • 12 Rounds12 Rounds• Both Ionic and Molecular EquationsBoth Ionic and Molecular Equations• At least four Acid Media EquationsAt least four Acid Media Equations• At least Four Basic media EquationsAt least Four Basic media Equations• Student Choice optional on Odd roundsStudent Choice optional on Odd rounds• Pre/Post Lab Homework – 20 equationsPre/Post Lab Homework – 20 equations

CHM 2045C StudentsCHM 2045C Students

Students have REDOX each semester:Students have REDOX each semester: • 12 Rounds12 Rounds• Both Ionic and Molecular EquationsBoth Ionic and Molecular Equations• At least four Acid Media EquationsAt least four Acid Media Equations• At least Four Basic media EquationsAt least Four Basic media Equations• Student Choice optional on Odd roundsStudent Choice optional on Odd rounds• Pre/Post Lab Homework – 20 equationsPre/Post Lab Homework – 20 equations

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Three Divisions: Three Divisions: The Advanced The Advanced

Division:Division:

CHM 2046C StudentsCHM 2046C Students /Chemistry Faculty /Chemistry Faculty

Students have REDOX each semester:Students have REDOX each semester: • 10 Rounds- The Championship10 Rounds- The Championship• All Molecular EquationsAll Molecular Equations• At least two Acid/Basic/Neutral Media EquationsAt least two Acid/Basic/Neutral Media Equations• Mother/Father*/Son/Daughter EquationsMother/Father*/Son/Daughter Equations• Student Choice optional on Odd roundsStudent Choice optional on Odd rounds• Pre/Post Lab Homework – 20 equationsPre/Post Lab Homework – 20 equations• *or the Mother-in-law Equation*or the Mother-in-law Equation

CHM 2046C StudentsCHM 2046C Students /Chemistry Faculty /Chemistry Faculty

Students have REDOX each semester:Students have REDOX each semester: • 10 Rounds- The Championship10 Rounds- The Championship• All Molecular EquationsAll Molecular Equations• At least two Acid/Basic/Neutral Media EquationsAt least two Acid/Basic/Neutral Media Equations• Mother/Father*/Son/Daughter EquationsMother/Father*/Son/Daughter Equations• Student Choice optional on Odd roundsStudent Choice optional on Odd rounds• Pre/Post Lab Homework – 20 equationsPre/Post Lab Homework – 20 equations• *or the Mother-in-law Equation*or the Mother-in-law Equation

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Three Divisions: Three Divisions: The Advanced The Advanced

Division:Division:

CHM 2045C StudentsCHM 2045C Students

Students have REDOX each semester:Students have REDOX each semester: • 12 Rounds12 Rounds• Mostly Molecular EquationsMostly Molecular Equations• At least four Acid Media EquationsAt least four Acid Media Equations• At least Four Basic media EquationsAt least Four Basic media Equations• Student Choice optional on Odd roundsStudent Choice optional on Odd rounds• Pre/Post Lab Homework – 20 equationsPre/Post Lab Homework – 20 equations

CHM 2045C StudentsCHM 2045C Students

Students have REDOX each semester:Students have REDOX each semester: • 12 Rounds12 Rounds• Mostly Molecular EquationsMostly Molecular Equations• At least four Acid Media EquationsAt least four Acid Media Equations• At least Four Basic media EquationsAt least Four Basic media Equations• Student Choice optional on Odd roundsStudent Choice optional on Odd rounds• Pre/Post Lab Homework – 20 equationsPre/Post Lab Homework – 20 equations

1212REDOX Balancing REDOX Balancing MethodsMethods

Emphasize Ion Electron MethodEmphasize Ion Electron Method(also know as Help Equation Method or half Equation Method)(also know as Help Equation Method or half Equation Method)

(The Dr. Cahill Story from 1966)(The Dr. Cahill Story from 1966)

Beginners are taught only the Ion Electron!Beginners are taught only the Ion Electron!

Advanced are taught both Ion-Electron Advanced are taught both Ion-Electron And Electron Transfer And Electron Transfer (or the Oxidation State Method)(or the Oxidation State Method)

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Balancing a Redox Equation by the Half-Reaction Method

• 1. Write the unbalanced net ionic equation if this is not already done for you. Refer to the solubility rules to determine which species will ionize and which remain molecular.

• 2. Separate the net ionic equation into two unbalanced half reactions.

• 3. Balance each half-reaction for all atoms other than Oxygen and/or Hydrogen.

• 4. Balance each half-reaction for O by adding H2O to the side with fewer O until they are in balance.

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Balancing a Redox Equation by the Half-Reaction Method

• 5. Balance each half-reaction for H by adding H+ to the side with less H until they are in balance.

• 6. Balance each half-reaction for charge by adding electrons to the side with greater positive charge (or less negative charge) until charges are in balance.

• 7. Multiply one or both half-reactions by suitable coefficients to make the electron count the same in both half-reactions (electrons lost = electrons gained).

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Balancing a Redox Equation by the Half-Reaction Method

• 8. Add the two balanced half-reactions together. Cancel electrons (make sure they are the same number) and any other species that appear on both sides of the equation.

• 9. Check to make sure the equation is balanced for atoms and charges on either side.

• 9 ½ . If balancing in base, add enough OH- to each side to convert any H+ on one side to H2O and leave that number of OH- on the other side. Recheck the water balance as this process creates water.

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Balancing a Redox Equation by the Half-Reaction Method

• 10. Rewrite the equation and check atom and charge balance. This is the acid test: if they are balanced you have done it correctly!

• 11. If the equation was originally a total molecular equation, substitute the net balanced ionic equation into the molecular equation and balance the spectator ions by inspection.

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Tips on Balancing Tips on Balancing EquationsEquations

• Never add ONever add O22, O atoms, or , O atoms, or OO2-2- to balance oxygen. to balance oxygen.

• Never add HNever add H22 or H atoms to or H atoms to balance hydrogen.balance hydrogen.

• Be sure to write the correct Be sure to write the correct charges on all the ions.charges on all the ions.

• Check your work at the end Check your work at the end to make sure mass and to make sure mass and charge are balanced.charge are balanced.

• PRACTICE!PRACTICE!

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2626The daughter is a Warm up!

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3030Ultimate Challenge: The Mother

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Contacts:

• Joseph Langat: jlangat@fscj.edu

• Kathleen Laurenzo: klaurenz@fscj.edu

• John Taylor johtaylor@fscj.edu