Ch. 9: Lesson 2-Intro to Redox Reactions-
Ch. 9: Lesson 2-Intro to Redox Reactions-
Brief Charge ReminderBrief 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 ReductionOxidation 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
Identifying what’s oxidized and what’s reduced
First assign oxidation #’s, then see how they change from start to finish
Ex: C + H2O CO + H2
First assign oxidation #’s, then see how they change from start to finish
Ex: C + H2O CO + H2
Oxidation/Reduction PracticeOxidation/Reduction Practice
MnO2 + 4 HCl MnCl2 + Cl2 + 2 H2OMnO2 + 4 HCl MnCl2 + Cl2 + 2 H2O
Redox ReactionsRedox 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
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 QuestionsConclusion 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 Reactions3 Forms of Redox Reactions
A + B AB Ex: 2 H2 + O2 2 H2O
AB A + B Ex: 2 NaCl 2 Na + Cl2
A + BC AC + B Ex: Zn + Cu(NO3)2 Zn(NO3)2 + Cu
A + B AB Ex: 2 H2 + O2 2 H2O
AB A + B Ex: 2 NaCl 2 Na + Cl2
A + BC AC + B Ex: Zn + Cu(NO3)2 Zn(NO3)2 + Cu
Recognizing Redox ReactionsRecognizing Redox Reactions
1. Single element(s) on either side of the equation
2 Li + Zn(NO3)2 2 Li(NO3) + Zn 2. Elements change oxidation # from reactant to
product
2 K + Cl2 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(NO3)2 2 Li(NO3) + Zn 2. Elements change oxidation # from reactant to
product
2 K + Cl2 2 KCl Increasing ox # means e- , was
Decreasing ox# means e- , was
AgentsAgents
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 + O2 2 SrOReduced: 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 + O2 2 SrOReduced: Oxidized:
Reducing agent: Oxidizing agent:
2 Cs + Br2 2 CsBr
3 Mg + N2 Mg3N2
4 Fe + 3 O2 2 Fe2O3
2 Cs + Br2 2 CsBr
3 Mg + N2 Mg3N2
4 Fe + 3 O2 2 Fe2O3
Ox:Rd:OxAg:RdAg:
Ox:Rd:OxAg:RdAg:
Ox:Rd:OxAg:RdAg:
Spectator IonsSpectator Ions
Spectators are atoms or ions without a charge change, just along for the ride
Spectators are atoms or ions without a charge change, just along for the ride
Cu + 2 AgNO3 Cu(NO3)2 + 2 Ag
Labeling Things In EquationsLabeling Things In Equations
Cu + 2 AgNO3 Cu(NO3)2 + 2 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 AgNO3 Cu(NO3)2 + 2 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 EquationsLabeling Things In Equations
Zn + 2 HCl ZnCl2 + H2
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 ZnCl2 + H2
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 EquationsLabeling Things In Equations
NaCl + AgNO3 AgCl + NaNO3
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 + AgNO3 AgCl + NaNO3
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 arenot redox reactions.
