Electrochemistry

Redox Reactions1.Galvanic Cells and Electrolytic Cells 2.

Kinetics

Reaction Rates 1.Integrated Rate Laws and Reaction Mechanisms2.Potential Energy Diagrams and Collision Theory 3.

Gaseous Equilibrium

Calculating Kca.ICE tablesb.Le Chatelier's Principle,c.Etc...d.

Intro to Equilibrium 1.

Solubility Equilibrium

Calculating Kspa.Predicting Precipitation b.Common Ion Effect,c.Etc...d.

Review1.

Acids & Bases and Aqueous Equilibrium

Equationsa.Acids and Bases1.

Titrations2.

Percent Ionization a.Aqueous Equilibrium 3.

Atomic Structure and Periodicity

Wave-Particle Theory 1.Quantum Numbers 2.Periodic Trends 3.

**More Detailed Course Outline on page 2 of green booklet

Chemistry 40S - Course Outline

Gr.12 Chemistry Page 1

http://www.google.ca/imgres?gurl=http://abbeyr.edublogs.org/files/2010/10/1D_periodic_table.jpg&imgrefurl=http://abbeyr.edublogs.org/neon/periodic -table-basics/&usg=__edS1Gv7gaZSj891OiYfgU-D23Xw=&h=502&w=730&sz=91&hl=en&start=21&zoom=1&tbnid=JSo9zvfmVvC48M:&tbnh=108&tbnw=157&ei=uY32Tc32O8ro0QH07_1F&prev=/search%3Fq%3Dthe%2Bperiodic%2Btable%26um%3D1%26hl%3Den%26biw%3D1366%26bih%3D575%26tbm%3Disch&um=1&itbs=1&iact=hc&vpx=402&vpy=298&dur=430&hovh=186&hovw=271&tx=108&ty=138&page=2&ndsp=21&ved=1t:429,r:16,s:21&biw=1366&bih=575

The Periodic Table

Gr.12 Chemistry Page 2

http://www.google.ca/imgres?imgurl=http://www.abcte.org/files/Chem-Formulas-and-Constants_.jpg&imgrefurl=http://www.abcte.org/files/chemistry_study_plan.pdf&usg=__KZFl0qH-3QthAbE1EMtEpoDphxs=&h=841&w=800&sz=49&hl=en&start=0&zoom=1&tbnid=bXOtTsoBT1pEZM:&tbnh=146&tbnw=139&ei=7I72TcXXK-bv0gG1jLHxDA&prev=/search%3Fq%3Dchemistry%2Bequation%2Bsheet%26um%3D1%26hl%3Den%26biw%3D1366%26bih%3D575%26tbm%3Disch&um=1&itbs=1&iact=rc&dur=305&page=1&ndsp=25&ved=1t:429,r:3,s:0&tx=63&ty=71&biw=1366&bih=575

Equation Sheet

Gr.12 Chemistry Page 3

http://www.google.ca/imgres?mgurl=http://www.nauticus.org/chemistry/images/eqoxi14.jpg&imgrefurl=http://www.nauticus.org/chemistry/chemoxi.html&usg=__R8S ZgYQTMSls-qf0DunDucOQ6vQ=&h=334&w=696&sz=252&hl=en&start=0&zoom=1&tbnid=RgFeAfb6UeG-GM:&tbnh=83&tbnw=173&ei=O5L2TeT9Gujn0QH61KXxDA&prev=/search%3Fq%3Drules%2Bfor%2Bassigning%2Boxidation%2Bnumbers%26um%3D1%26hl%3Den%26biw%3D1366%26bih%3D575%26tbm%3Disch&um=1&itbs=1&iact=hc&vpx=269&vpy=110&dur=305&hovh=83&hovw=173&tx=93&ty=44&page=1&ndsp=21&ved=1t:429,r:1,s:0&biw=1366&bih=575

Rules For Assigning Oxidation Numbers

Gr.12 Chemistry Page 4

http://www.google.ca/imgres?mgurl=http://www.chem.fsu.edu/chemlab/chm1045lmanual/redox/Srptable.jpg&imgrefurl=http://www.chem.fsu.edu/chemlab/chm1045lmanual/redox/index.html&usg=__CsW2gqocrv_zuvXdLk7Mxy0cPIA=&h=1200&w=1467&sz=227&hl=en&start=8&zoom=1&tbnid=sdL8emwZ6frJSM:&tbnh=123&tbnw=150&ei=6sz3TbLpGIXSsAP15pTYDA&prev=/search%3Fq%3Dredox%2Btable%26um%3D1%26hl%3Den%26sa%3DN%26biw%3D1366%26bih%3D575%26tbm%3Disch&um=1&itbs=1&biw=1366&bih=575

Red-Ox Table

Gr.12 Chemistry Page 5

http://www.google.ca/imgres?mgurl=http://intro.chem.okstate.edu/1215/lecture/chapter7/SolTab.gif&imgrefurl=http://intro.chem.okstate.edu/1215/lecture/chapter7/lecture92898.html&usg=__PPyKvQYBI1W4pDYisGwrCnhZxqQ=&h=451&w=510&sz=10&hl=en&start=0&zoom=1&tbnid=fewKMpTxK27JQM:&tbnh=123&tbnw=139&ei=DpL2TZCtIMbW0QG21bjoDA&prev=/search%3Fq%3Dsolubility%2Bchart%26um%3D1%26hl%3Den%26biw%3D1366%26bih%3D575%26tbm%3Disch&um=1&itbs=1&iact=hc&vpx=385&vpy=254&dur=297&hovh=123&hovw=139&tx=132&ty=81&page=1&ndsp=24&ved=1t:429,r:10,s:0&biw=1366&bih=575

Solubility Chart

Gr.12 Chemistry Page 6

BrightStorm

Offers online video tutorials on pretty much every topic in Chem 30S and 40S-

Actual teachers explaining the work (Step by Step)-

Easy to understand -

Includes interactive quizzes, practice problems, and study guides-

Also helps with physics and biology -

http://www.brightstorm.com/science•http://www.youtube.com/user/brightstorm2•

Spark Notes

Provides detailed explanations of every unit -

http://www.sparknotes.com/chemistry/•

Chemistry For Dummies

=> This review is a very basic/general one... and you have to have an understanding of certain concepts to know what I am ta lking about. So here are a few resources that you can refer to. They are easy to use and understand. I highly recommend using BrightStorm :)

Other Resources

Other Study Guides Page 7

Electronegativity and Trends 1.Assigning Oxidation Numbers2.Identifying Redox Reactions3.Electrochemistry Terms 4.Writing Balanced Half-Reactions 5.Making a Redox Table 6.Yee-Haw-Down-Right-Spontaneous Rule *7.Galvanic Cells/Electrochemical Cells/Voltaic Cells8.Inert Electrodes/Standard Hydrogen Electrode (SHE)/Changing the SHE9.Electrolytic Cells (aqueous and ,molten)10.Electrolysis Stoichiometry (Q=It and Faraday)11.

-these values help you to determine oxidation numbers (the higher its electronegativity value, the more likely the atom/ion will keep its charge)

Electronegativity - the ability of an atom in a compound to attract electrons 1.

http://www.grandinetti.org/Teaching/Chem121/Lectures/Electronegativity

Assigning Oxidation Numbers2.The oxidation number of a chemical species is a + or a - number corresponding to the apparent charge that an atom in a molecule or ion would have if the e- pairs in covalent bonds belonged entirely to the more electronegative atom.

-

Example: C6H12O6

Oxygen is more electronegative than Carbon and Hydrogen. Therefore, the oxidation number for O is -2

Refer to the oxidation rules to figure out Hydrogen (it usually keeps its charge). Therefore, H=+1

C(6) + H(12) + O(6) = 0

C(6) + 1(12) + -2(6) = 0

C(6) = 12 - 12

C(6) = 0

Noble Gases EN value = 0

=> Redox reactions involve oxidation and reduction of chemicals

Intro to Redox Reactions

Electrochemistry Page 8

C(6) = 0

C = 0

C6 H12 O6

0 +1 -2

Example: Assigning Oxidation Numbers in Net Ionic Equations

- Gr.12 Chemistry => Rules For Assigning Oxidation Numbers **Keep checking Rules For Assigning Oxidation Numbers:

Potassium Iodide solution reacts with diatomic Chlorine Gas

K I + Cl2 => KCl +I2+1-1 0 +1-1 0

K^+ + I + Cl2 => K^+ + Cl + I2

2I^- + Cl2 => 2Cl^- + I2-1 0 -1 0

*Solids/ions by themselves (such as Cl2) without a given charge have an oxidation number/charge of zero

*Questions like this one on page 8 of green booklet !

Electrochemistry Page 9

Electrochemistry Terms/Things to Keep in Mind4.

Losing Electrons = Oxidation

Gaining Electrons = Reduction

LEO the lion goes GER-

Reducing Agent (RA) causes the reduction of another chemical in the reaction. It is oxidized -

Oxidizing Agent (OA) causes the oxidation of another chemical in the reaction. It is reduced -

Cathode - where reduction occurs -

Anode - where oxidation occurs-

Electrolytic Cells - cells containing nonspontaneous chemical reactions-

Voltaic/Galvanic Cells - electrochemical cells containing spontaneous chemical reactions-

Yee-Haw-Down-Right-Spontaneous Rule For Predicting Redox Reactions (half reactions)7.

Combinations of chemicals that react are said to result in a spontaneous reaction. Non spontaneous reactions don't react.

-

The redox table helps to predict whether or not a redox reaction is spontaneous. -

In redox reactions, the Strongest Oxidizing Agent (SOA/Right Side) always reacts with the Strongest Reducing Agent (SRA/Left Side) as long as the SOA is located higher up on the redox table than the SRA.

-

Important steps to know for predicting and writing balanced net ionic equations from half reactions

List all chemicals present and determine SOA and SRA-

Write out half reactions and flip the SRA (don't forget to change the sign for voltage)-

Determine whether or not a reaction occurs (Yee-Haw-Down-Right-Spontaneous Rule or Positive Overall Cell Potential)

-

If so, write the balanced NIE-

5 types of reactions

Synthesis 1.Decomposition2.Single Displacement 3.Double Displacement* 4.Combustion5.

*Of these five reactions only the DOUBLE DISPLACEMENT reaction is NOT a redox reaction. This is because reduction/oxidation doesn't occur.

Question:

Will Lead react with Copper(II) ions? ANSWER: Yes 1.

FLIP THIS ONE!

NIE: Cu2+ +Pb(s) <---> Cu(s) + Pb2+ 0.47V

We can already tell that this reaction is going to be a spontaneous one because Lead is down and to the right of Copper(II) ion.

Positive… Therefore it is spontaneous

Identifying Redox Reactions 3.

Electrochemistry Page 10

**For these reactions and when writing the NIE, always make sure that the electrons, the charge, and the number of atoms are always balanced.

Electrochemistry Page 11

=> Instead of just using half reactions to come up with a Net Ionic Equation (NIE), the NIE can also be separated into half reactions (which can be found on the redox table)

For Example:

Cu(s) + 2Ag+(aq) <----> Cu2+(aq) + 2Ag(s) **Remember charges must also be balanced

Ox1/2rx Cu(s) ---> Cu2+(aq) + 2e-

Red1/2rx Ag+(aq) + 1e- ---> Ag(s)

Writing Balanced Half Reactions5.

Electrochemistry Page 12

**Lab

Given these three reactions, we must make a redox table….

Al(s) + Ag+ ---> Al3+ + Ag(s)1.Al(s) + Ni2+ ---> Al3+ + Ni(s)2.Ni(s) + Ag+ ---> Ni2+ + Ag(s)3.

Split up each NIE into half reactions. By referring to the redox table, you will be able to find the Oxidation Half Reaction (Ox1/2rx) and the Reduction Half Reaction (Red1/2rx)

Ox1/2rx Al ---> Al3+ + 3e-1.Red1/2rx Ag+ +1e- ---> Ag

Ox1/2rx Al ---> Al3+ + 3e-2.Red1/2rx Ni2+ + 2e- ---> Ni

Ox1/2rx Ni ---> Ni2+ + 2e-3.Red1/2rx Ag+ + 1e- ---> Ag

Making the redox table…

Make chart -

Write as reduction half reaction (as seen on the redox table)-

List from strongest to weakest oxidizing agent (OA)-

x Ni2+ Ag+ Al3+

Ni(s) x Reaction No Reaction

Ag(s) No Reaction x No Reaction

Al(s) Reaction Reaction x

Finished Redox Table

**You shouldn't have to look at your redox table for questions like this one (when you are given the NIE's)

**The ion with the most spontaneous reactions in its column is the SOA… and then you just go from there

**Remember: If a reaction is spontaneous in one direction, it won't be in the other direction

For Example: Once you know that there is a spontaneous reaction between Ni(s) and Ag+, you'll know that there won't be a reaction between Ag(s) and Ni2+

SOA Ag+ + e- ---> Ag Ni2+ + 2e- ---> Ni Al3+ + 3e- ---> Al SRA

A good thing to know…

**These reaction aren't balanced … charges don't match up

Making a Redox Table6.

Electrochemistry Page 13

A good thing to know…

If you are given an equation that looks like this, Al3+ + Ag(s) ---> No Reaction

Then you should know that… Al(s) + Ag+ ---> Al3+ + Ag(s) will create a spontaneous reaction

Electrochemistry Page 14

http://web.fccj.org/~ethall/2046/ch18/galvanic.htm

REDUCTION OXIDATION

** Don't forget to list the anions and cations!

Anions: SO42- => in class we usually use No3-Cations: Zn2+, Cu2+, Na+

Ecell is positive: This reaction is spontaneous!

Short form of representing this electrochemical cell :

SOA SRA

Cu(s) I Cu2+(aq) II Zn(s) I Zn2+(aq)

Galvanic Cells/Electrochemical Cells/Voltaic Cells8.

Electrochemistry Page 15

- examples include: C(s) and Pt(s)

Inert electrodes - in some cases, solids aren't part of the redox reaction. Yet a solid is still required for electrons to pass through an external circuit (even though the solid doesn't react)

Standard Hydrogen Electrode - (SHE) allows us to generate a list of Standard Reduction Potential's (SRP's) that can be used to determine the Ecell of any two combo's of reduction and oxidation 1/2 reactions.

Changing the SHE

**Making Ecell of Lithium = Zero

Cl2 + 2e- ---> 2Cl-Fe2+ + 2e- ---> FeLi+ + e- ---> Li

Er = 1.36V +3.04 = 4.40VEr = -o.44V + 3.04 = 2.60VEr = -3.04V + 3.04 = 0.00V

Ecell = 1.80V

Before

Er = 1.36VEox = 0.44V

Ecell = 1.80V

After

Er = 4.40VEox = -2.60V

Ecell = 1.80V

Inert Electrodes/Standard Hydrogen Electrode (SHE)/Changing the SHE

9.

Electrochemistry Page 16

http://chemed.chem.purdue.edu/genchem/topicreview/bp/ch20/faraday.php

Electrolytic Cells (aqueous and ,molten)10.

Electrochemistry Page 17

Electrochemical Cells Electrolytic Cells

Spontaneous? Yes No

Ecell? Positive Negative

Cathode? SOA --> reduction (positive) Negative electrode

Anode? SRA --> oxidation (negative) Positive electrode

e- flow Anode to Cathode Anode to Cathode

Ion movement Anions to Anions/Cations to Cations

Electrochemical Cells vs. Electrolytic Cells

Electrochemistry Page 18

Rates - the ratio of reactant rates over time Δreactant/Δtime1.Determining Rates 2.Average vs. Instantaneous Rates 3.Equating Rates and Rate Stoichiometry 4.Rate Laws5.Potential Energy Diagrams 6.Reaction Mechanisms 7.Collision Theory (5 factors affecting rates)8.

Change in Volume/Pressure (gas)a.Change in Mass of Solidb.Change in pH (OH- (basic) H+ (acidic))c.Change in Conductivity (ions)d.Change in Colour e.

Determining Rates (Physical Data)2. Average vs. Instantaneous Rates 3.

Slope 1: average rate of disappearance of reactant

Δreactant/Δtime

Slope 2: instantaneous rate of disappearance of reactant

**LabKinetics/Rates

Kinetics Page 19

Reaction Mechanisms 7.

http://www.kentchemistry.com/RegentsExams/regents_jun_2003_41_50.htm

A: Reactant enthalpyB: Activation energy (Ea) C: Activated complexD: Product enthalpyE: Change in enthalpy (forward)F: Ea of the reverse reactionG: Change in enthalpy (reverse)

EF

G

http://www.sciencecontrol.com/endothermic-vs-exothermic.html

**This is an EXOTHERMIC reaction

Potential Energy Diagrams 6.

Kinetics Page 20

Temperature a.An increase in temperature corresponds to increase Kinetic Energy (KE)-

Particles are moving faster and can collide more frequently -

Causes the rate to increase -

http://www.umich.edu/~essen/html/03chap/html/collision/index.htm

Concentration/Surface Area => More collisions, higher rate b.More molecules means more frequent collisions. Therefore more successful collisions-

Increased concentration results in increased reaction rate-

Addition of a catalyst (lower Ea)c.A catalyst increases the rate without being used up by providing an alternate, lower energy pathway for the reaction

-

http://yite12ibchem.blogspot.com/2011_05_01_archive.html

Nature of Reactants (Ions in solution) + <---> -d.Aqueous ions in solution react instantaneously, as opposed to uncharged gas molecules that must rely on random collisions

-

Oppositely charged ions are attracted to each other and are able to flow in a fluid medium, so reaction is instantaneous and Activation Energy (Ea) is essentially nil

-

Collision Theory (five factors affecting rates)8.

Kinetics Page 21