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

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.