Ch. 9: Lesson 2 -Intro to Redox Reactions- Ch. 9: Lesson 2 -Intro to Redox Reactions-

Brief Charge Reminder  Electrons have a charge  Neutral atoms have an overall charge of  Adding an e- makes charge go  Removing an e- makes charge go  Electrons have a charge  Neutral atoms have an overall charge of  Adding an e- makes charge go  Removing an e- makes charge go

Oxidation and Reduction  Reduction is a gain of electrons (charge is reduced)  Oxidation is a loss of electrons (charge is increased)  Ag  Ag = =  Cl  Cl = =  Reduction is a gain of electrons (charge is reduced)  Oxidation is a loss of electrons (charge is increased)  Ag  Ag = =  Cl  Cl = = + - Equation with e- Process

 Reduction reduces charge  Oxidation is just the other one  Reduction reduces charge  Oxidation is just the other one

Identifying what’s oxidized and what’s reduced  First assign oxidation #’s, then see how they change from start to finish Ex: C + H 2 O  CO + H 2  First assign oxidation #’s, then see how they change from start to finish Ex: C + H 2 O  CO + H 2

Oxidation/Reduction Practice MnO HCl  MnCl 2 + Cl H 2 O

Redox Reactions  Redox reactions involve REDuction and OXidation  SAT Word Alert: PORTMANTEAU -THIS MEANS-  Both have to happen at the same time  Redox reactions involve REDuction and OXidation  SAT Word Alert: PORTMANTEAU -THIS MEANS-  Both have to happen at the same time

Remembering How Redox Works  LEO says GER:  Losing e- is  Gaining e- is  OIL RIG  Oxidation is e-  Reduction is e-  LEO says GER:  Losing e- is  Gaining e- is  OIL RIG  Oxidation is e-  Reduction is e-

Conclusion Questions  For Now: Review book page 162, # 11-15, on back of paper slips to hand in before you leave  For HW: same page, #16-25, in notebooks  For Now: Review book page 162, # 11-15, on back of paper slips to hand in before you leave  For HW: same page, #16-25, in notebooks

Ch. 9: Lesson 3 -Recognizing Redox Reactions & Their Parts- Ch. 9: Lesson 3 -Recognizing Redox Reactions & Their Parts-

3 Forms of Redox Reactions  A + B  AB  Ex: 2 H 2 + O 2  2 H 2 O  AB  A + B  Ex: 2 NaCl  2 Na + Cl 2  A + BC  AC + B  Ex: Zn + Cu(NO 3 ) 2  Zn(NO 3 ) 2 + Cu  A + B  AB  Ex: 2 H 2 + O 2  2 H 2 O  AB  A + B  Ex: 2 NaCl  2 Na + Cl 2  A + BC  AC + B  Ex: Zn + Cu(NO 3 ) 2  Zn(NO 3 ) 2 + Cu

Recognizing Redox Reactions  1. Single element(s) on either side of the equation 2 Li + Zn(NO 3 ) 2  2 Li(NO 3 ) + Zn  2. Elements change oxidation # from reactant to product  2 K + Cl 2  2 KCl  Increasing ox # means e-, was  Decreasing ox# means e-, was  1. Single element(s) on either side of the equation 2 Li + Zn(NO 3 ) 2  2 Li(NO 3 ) + Zn  2. Elements change oxidation # from reactant to product  2 K + Cl 2  2 KCl  Increasing ox # means e-, was  Decreasing ox# means e-, was

Agents  Reducing agents cause something else to be reduced, but get oxidized themselves  Oxidizing agents cause something else to be oxidized, but get reduced themselves 2 Sr + O 2  2 SrO Reduced: Oxidized: Reducing agent: Oxidizing agent:  Reducing agents cause something else to be reduced, but get oxidized themselves  Oxidizing agents cause something else to be oxidized, but get reduced themselves 2 Sr + O 2  2 SrO Reduced: Oxidized: Reducing agent: Oxidizing agent:

2 Cs + Br 2  2 CsBr 3 Mg + N 2  Mg 3 N 2 4 Fe + 3 O 2  2 Fe 2 O 3 2 Cs + Br 2  2 CsBr 3 Mg + N 2  Mg 3 N 2 4 Fe + 3 O 2  2 Fe 2 O 3 Ox: Rd: OxAg: RdAg: Ox: Rd: OxAg: RdAg: Ox: Rd: OxAg: RdAg:

Spectator Ions  Spectators are atoms or ions without a charge change, just along for the ride Cu + 2 AgNO 3  Cu(NO 3 ) Ag

Labeling Things In Equations Cu + 2 AgNO 3  Cu(NO 3 ) Ag  Make sure equation is balanced, find ox# for each species  What is being oxidized?  What is being reduced?  What is the oxidizing agent?  What is the reducing agent? Cu + 2 AgNO 3  Cu(NO 3 ) Ag  Make sure equation is balanced, find ox# for each species  What is being oxidized?  What is being reduced?  What is the oxidizing agent?  What is the reducing agent? Any spectator ions?

Labeling Things In Equations Zn + 2 HCl  ZnCl 2 + H 2  Make sure equation is balanced, find ox# for each species  What is being oxidized?  What is being reduced?  What is the oxidizing agent?  What is the reducing agent? Zn + 2 HCl  ZnCl 2 + H 2  Make sure equation is balanced, find ox# for each species  What is being oxidized?  What is being reduced?  What is the oxidizing agent?  What is the reducing agent? Any spectator ions?

Labeling Things In Equations NaCl + AgNO 3  AgCl + NaNO 3  Make sure equation is balanced, find ox# for each species  What is being oxidized?  What is being reduced?  What is the oxidizing agent?  What is the reducing agent? NaCl + AgNO 3  AgCl + NaNO 3  Make sure equation is balanced, find ox# for each species  What is being oxidized?  What is being reduced?  What is the oxidizing agent?  What is the reducing agent? This is double replacement. Double replacement’s are not redox reactions.