Teaching High School Chemistry
  • Introduction
  • Book
  • Blog
  • Topic List
  • Teaching Resources
  • Biography
  • Contact

organic chemistry -- chemical reactions

5/28/2014

0 Comments

 
This post is about Chemical Reactions typical in Organic Chemistry.

Objectives:

1.  Describe the characteristics of a substitution reaction.

2.  List the structures that are products of an addition reaction.

3.  Describe esterification and saponification.

4. Describe the characteristics of the formation of a polymer.

This video contains a brief description of the substitution reaction:
A benzene ring has the formula of C6H6 and is carbon bonded to itself in a ring with a single hydrogen bonded to each carbon.  Each carbon can have 4 bonds, there are 3 alternating double bonds in the ring and it is considered a "resonance structure" -- here is a video to better illustrate the compound as well as provide the classic story:
If there are double or triple bonds in a structure, they can be "opened" up and substances can be added -- an addition reaction, as explained in the following video:
Here is a brief overview of esterification and saponification reactions:
The focus here is to be able to recognize these reactions.

These reactions usually take a long time and use organic solvents -- usually they are not encountered in the lab until studying Organic Chemistry at a college level.

There are several videos online demonstrating soapmaking, and I have performed a lab making soap in class.  At this point in the school year, you may not want to spend the time on this lab, so I'm going to talk about one lab that is easy to pull together.

Here is a discussion of polymers (plastics) with a nice history of the origin of the need for polymers. Given our issues with the disposal and/or recycling of plastics, this is very interesting:
A cross-linked polymer can be made easily with white glue and sodium tetraborate solution (easily found as solid Borax in the Laundry section of the grocery store). 

I have a description of this lab in my lab book "Chemistry on a Budget" at amazon.com -- it's only $20! 
http://www.amazon.com/Chemistry-Budget-Marjorie-R-Heesemann/dp/0578129159/ref=sr_1_1?s=books&ie=UTF8&qid=1389410170&sr=1-1&keywords=chemistry+on+a+budget

Each lab is presented with two possible report formats -- both labs use the same procedure but each has a different conclusion -- one with 10 questions to be answered as a conclusion, the other with a full laboratory report required.  This gives the teacher the option of what type of report is desired, and each version is designed to be just two pages.  This way the teacher can photocopy just one 2-sided page per student (saves paper).  

*I'd love to hear from you!  Your feedback would really help me to focus on your needs!  There should be a "Contact" form below, or click on the "Contact" tab on the top right of this page.  

An end of the year laboratory that might be fun is tie dyeing -- I will describe more about it in Sunday's post.

From now on, I am going to be posting on Sundays only.  If I change the schedule, I'll let you know!

Have a good rest of the week!
0 Comments

organic chemistry -- organic compounds

5/25/2014

0 Comments

 
I hope you're having a great Memorial Day weekend!  Continuing with the topic of Organic Chemistry, today I am focusing on types of organic compounds other than alkanes, alkenes and alkynes.

Objectives:

1.     Identify a molecule's functional group, including those for alcohols, carboxylic acids, ethers,  esters, aldehydes, and ketones.

2. Explain physical property differences in a class of organic compounds based on their molecular structure.

Table R (page 8)  in the NYS Regents Chemistry Reference table has a chart of structures that's a very handy reference:

http://www.kentchemistry.com/newRT.pdf

This is a very brief video, but a useful overview of organic compounds other than straight-chain carbon compounds:
Here is another brief video describing how to name compounds with functional groups:
Notice that he also talks about the properties of the compound and their polarity and properties b/c of these functional groups. 

Finally, here is a full lecture (30 minutes), at a college-level, talking about organic compounds -- it's helpful because it talks about these functional groups and the properties of the various compounds more in-depth:
This webpage with links to several Organic Chemistry topics:

http://www.delsearegional.us/Academic/Classes/highschool/science/chemistry/firstyear/Notes/academic/Unit10/Unit10.html

This worksheet contains practice identifying organic compounds with functional groups, and provides more practice drawing stuctures from the names.  It's the sixth item down on the list titled "Functional Groups" :

http://www.penfield.edu/webpages/tabraham/resources.cfm?subpage=1498914

Here's a worksheet focusing on Organic Compounds that are more complex than the straight-chain hydrocarbons -- the 2nd of the two pages would be good for the introductory chemistry student:

http://www.kentschools.net/ccarman/files/2013/08/chemistry-naming_organic_compounds_ws_2.pdf

There aren't too many labs for these compounds with functional groups b/c exposure to organic compounds is not really good for you in the long run -- your body absorbs these compounds (think fat soluble) instead of flushing them out of your system (water soluble), and there are some potential carcinogens out there.

Here are several ways to approach a demonstration you may know as the "Whoosh bottle"  -- where the combustion of isopropyl alcohol in a large water bottle makes a "whoosh" sound.  Notice that they all have their goggles on!
And here is the Flinn page with instructions on how to perform this combustion of isopropyl alcohol demonstration:
https://www.flinnsci.com/media/484580/95010-r.pdf

If you choose to perform this, be careful.  WEAR GOGGLES!!!  I don't like that they're not wearing goggles in this experiment,  but here's an example of this demo going awry:
I think the laughter is nervous laughter.  It's good that the teacher had the fire  extinguisher at the ready!

My next post will contain information about Organic Reactions, as well as lab possibilities, including tie dyed t-shirts!

Check out my lab book "Chemistry on a Budget" at amazon.com -- it's only $20! 
http://www.amazon.com/Chemistry-Budget-Marjorie-R-Heesemann/dp/0578129159/ref=sr_1_1?s=books&ie=UTF8&qid=1389410170&sr=1-1&keywords=chemistry+on+a+budget

Each lab is presented with two possible report formats -- both labs use the same procedure but each has a different conclusion -- one with 10 questions to be answered as a conclusion, the other with a full laboratory report required.  This gives the teacher the option of what type of report is desired, and each version is designed to be just two pages.  This way the teacher can photocopy just one 2-sided page per student (saves paper).  

*I'd love to hear from you!  Your feedback would really help me to focus on your needs!  There should be a "Contact" form below, or click on the "Contact" tab on the top right of this page.  

Have a good week!




0 Comments

Organic chemistry -- alkanes, alkenes & alkynes

5/21/2014

0 Comments

 
I mentioned my posting schedule in Sunday, 5/18's blog post -- basically, I'm posting Sunday and Wednesday through the end of May, and Sundays from June, 2014 on.  The posts will be later in the day, between 4pm and 7pm.  

Finishing up the school year, some teachers are covering Organic Chemistry, and that is the topic of the next three posts.

Objectives:

1.  Classify hydrocarbons as alkanes, alkenes or alkynes; draw structural formulas for hydrocarbon molecules if given their molecular formulas.

2.  Name hydrocarbons using the IUPAC system and write the structural formula given its name.

3.  Construct all possible structural isomers for different hydrocarbons.

This topic is a good revisit of  the topic of Bonding and is useful for some review.  Here's an introduction of the basics of Organic Chemistry:

This next video (30 minutes) gets into the basics of formula naming and writing with a more in-depth segment focusing on the basics a little more slowly:
This teacher goes through long examples and clarifies when dashes and commas are inserted.  It's a nice overview!

BTW, there's a handy summary of organic information on the NYS Regents Chemistry Reference Table.  A link for it is listed in my Teaching Resources (link above).

Here's a powerpoint presentation about Naming Organic Compounds that might be useful:

http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=0CCYQFjAA&url=http%3A%2F%2Fwww.chalkbored.com%2Flessons%2Fchemistry-11%2Fhydrocarbon-nomenclature.ppt&ei=dF17U9iHFMKIqga4xYHQCg&usg=AFQjCNGv8stBa674PAtvmCYaIapwGjWDvQ&bvm=bv.67229260,d.b2k


I remember saying "methyl ethyl propyl butyl" over and over while I was lecturing to get students to remember those prefixes.    The acronym I learned was "monkeys eat purple bananas" -- use whatever works!

This page contains a full overview of formula writing and naming -- you might not want to print the entire post, but there may be some useful sections:

http://butane.chem.uiuc.edu/cyerkes/Chem104A_BFA05/Genchemref/nomenclature_rules.html

Continuing with the introduction of hydrocarbons is this video about unsaturated hydrocarbons. 

Your students may recognize the terms saturated and unsaturated as they have heard about saturated and unsaturated fats.  Saturated fat (such as butter or lard) is solid at room temperature as it has a greater mass/higher melting point, and unsaturated fat (such as olive or corn oil) is liquid at room temperature as it has lower mass/lower melting point.
He goes through various chemical reactions related to "opening" the double or triple bond -- I will go into that topic more in depth next week.

This is very brief worksheet:

http://misterguch.brinkster.net/PRA033.pdf

This is a worksheet with answers, but it has some examples past the alkane, alkene and alkyne series:

http://www.chemguide.co.uk/basicorg/questions/q-names1.pdf

Here's a cute online quiz:
http://www.bbc.co.uk/bitesize/quiz/q53403449


This is a little tougher, but it has answers:

http://www.claytonschools.net/cms/lib/MO01000419/Centricity/Domain/244/organicnomenclature%20wksht%20key.pdf

The typical lab at the high school chemistry level is using molecular model kits to build all of the isomers of the first five alkanes.

If you don't have molecular model kits in the chemistry department, try the biology department to see if they have kits you can use.

Here's are some examples of labs building molecular models and isomers:

http://betterlesson.com/document/315405/molecular-models-lab-activity-lewis-dot-doc

http://www.morganchem.com/PARENTS/OrganicIsomerLab.pdf

Here's a lab I used a lot (it's not a great copy):
http://www.cpet.ufl.edu/wp-content/uploads/2013/03/3-D-Models-of-Covalent-Molecules-Activity-Exploring-Covalent-Bonding.pdf

This lab is interesting b/c it's all about the isomers of heptane.  It is probably a college lab, but could be a good enrichment project for a student:

http://www.evanschemistrycorner.com/Labs/Organic/L11-3A_Naming_the_Isomers_of_Hydrocarbons.pdf

This lab is several pages, but if desired, just print/use the first page:
http://ck042.k12.sd.us/Unit%207%20Docs/modelslab.pdf

I hope the school year is ending well for you!  One end of year activity I used to perform was to tie dye t-shirts -- I even had a tie-dyed lab coat!   I'll post some lab instructions on a later post.

I am selling my lab book "Chemistry on a Budget" at amazon.com for only $20!  Check it out:
http://www.amazon.com/Chemistry-Budget-Marjorie-R-Heesemann/dp/0578129159/ref=sr_1_1?s=books&ie=UTF8&qid=1389410170&sr=1-1&keywords=chemistry+on+a+budget

Each lab is presented with two possible report formats -- both labs use the same procedure but each has a different conclusion -- one with 10 questions to be answered as a conclusion, the other with a full laboratory report required.  This gives the teacher the option of what type of report is desired, and each version is designed to be just two pages.  This way the teacher can photocopy just one 2-sided page per student (saves paper).  

*I'd love to hear from you!  Your feedback would really help me to focus on your needs!  There should be a "Contact" form below, or click on the "Contact" tab on the top right of this page.  

Have a good end of the week!
0 Comments

electrochemistry -- electrolytic cells

5/18/2014

0 Comments

 
This post should finish the topic of electrochemistry by discussing Electrolytic Cells.  

Objectives:

1.  Explain the parts and chemical reactions in an electrolytic cell.

2.  Distinguish between electrolytic and electrochemical cells, and list some applications of each.

3.  Describe how commercial cells produce an electric current; explain the process of corrosion.

An electrolytic cell is a non-spontaneous reaction (- Eo total) that is connected to a battery to provide the energy for the reaction. 

Picture
Remember that if the reaction is reversed then the Eo value has the opposite sign (for example, instead of + it would be - ).

Here is a video providing an overview of electrolytic cells:
Fortunately, the acroynm "LEO GER" still applies.  The only change is the electric charges on the anode and cathode.

Here is another video briefly describing an electrolytic cell:
Notice that it contrasts electrolytic and electrochemical cells.  Personally, I remember the charges on the electrolytic cell more easily than the electrochemical cell because I remember that opposites attract (the cathode is negative to attract the positive cation, and the anode is positive to attract the negative anion).

This link is to several pages of notes, and the last page contains a worksheet:

http://mrrumbolt.weebly.com/uploads/4/9/5/2/4952485/electro6_electrolytic_cellsyd_no_solns.pdf

This page has questions AND answers, but it's a useful overview:

http://www.mro-chemweb.com/honchem/docs/hoans/electrowksht1.pdf

Here's a simple worksheet focusing on electrolysis:

http://sunwestscience.wikispaces.com/file/view/Chemistry+30+-+7.8+-+Electrolysis+-+Worksheet.pdf

This is a link to a summary/overview but then has various worksheets about redox, ending with worksheets on electrolysis:

http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=99&ved=0CGYQFjAIOFo&url=http%3A%2F%2Fteacherweb.com%2FCT%2FNewMilfordHighSchool%2FMissLandgrebe%2FAP-C20-Electrochemistry-handout.doc&ei=vbZ3U5PUBYyYqAaC9YCYCA&usg=AFQjCNEgNVw9fDIdDatk3M4YDvlkQ01buA


I've never made a lemon battery, but it's an interesting idea (btw it doesn't have to be performed in a lemon...)
Perhaps set up the same electrodes but simply in an acetic acid medium?
Here is another electrolytic demonstration idea:
https://www.flinnsci.com/media/621556/91646.pdf

Here is a page describing how a battery works:
http://www.edinformatics.com/math_science/how_does_a_battery_work.htm

Here is an interesting video demonstrating how electrolysis can be used to counteract the effects of rusting on tools:
Here is another video about the rusting of iron:
And here is a segment showing how rust can be removed from a tool --the post is about woodworking, but it's a very interesting demonstration:
Let me know if you have tried any of these ideas!

Looking at my schedule, I will post Wednesdays and Sundays through the end of May (mainly about organic chemistry), and as of June, I will post on Sundays.  My posts will be in the evenings from now on.

I am selling my lab book "Chemistry on a Budget" at amazon.com for only $20!  Check it out:
http://www.amazon.com/Chemistry-Budget-Marjorie-R-Heesemann/dp/0578129159/ref=sr_1_1?s=books&ie=UTF8&qid=1389410170&sr=1-1&keywords=chemistry+on+a+budget

Each lab is presented with two possible report formats -- both labs use the same procedure but each has a different conclusion -- one with 10 questions to be answered as a conclusion, the other with a full laboratory report required.  This gives the teacher the option of what type of report is desired, and each version is designed to be just two pages.  This way the teacher can photocopy just one 2-sided page per student (saves paper).  

*I'd love to hear from you!  Your feedback would really help me to focus on your needs!  There should be a "Contact" form below, or click on the "Contact" tab on the top right of this page.  

Have a good week!

0 Comments

electrochemistry -- electrochemical cells

5/14/2014

0 Comments

 
Continuing with the subject of Electrochemistry, a big topic is Electrochemical Cells.

Objectives:

1. Describe the production of electric current in an electrochemical (galvanic or voltaic) cell.

2.  Identify the chemical reactions in an electrochemical (aka galvanic or voltaic) cell.

3. Define cell potential and describe how it is determined.

4. Define the standard electrode potential of an electrode.

5. Compute the standard emf of an electrochemical cell using standard electrode potentials.


Here is an overview of electrochemical cells:
I'm focusing on spontaneous reactions with a (+)Eo; this video does talk briefly about electroplating or a nonspontaneous reaction.  I will examine nonspontaneous electrochemical reactions (electrolysis) more in depth during my next post.

Notice that a positive value for Eo is a spontaneous, versus a negative delta H being spontaneous.  I usually point this out to my students.

Here's a brief video presenting an animation of a galvanic cell:
I required my students to be responsible for several items of information when given an electrochemical cell combination.

For example, given a copper/copper nitrate and a zinc/zinc nitrate combination, identify the following:

1) What is the Eo of the cell?  Show the calculation.

2) Which metal oxidizes (is the anode) ?  What is the electric charge of this anode?

3) Which metal reduces (is the cathode)?  What is the electric charge of this cathode?

4) Which electrode is gaining mass?  Which electrode is losing mass?

5) What is the direction of the electrons through the voltmeter?

To answer these questions, a list of standard electrode potentials is necessary.  Here's one example:

Picture
With a table of Standard Electrode Potentials, you actually have twice as much information than the table shows directly.  The reverse reaction has an equal value but opposite sign (+or -)  on its electrode potential.

Of the two reactions, the reaction higher on the chart (having a higher Eo value) will be the reduction half-reaction.

The other (lower) reaction is reversed and the sign on the listed Eo value is reversed also, producing the oxidation half-reaction. 

A pneumonic to remember what happens at which electrode is "an ox / red cat" where the "anode is where oxidation occurs" and the "cathode is where reduction occurs" .

In this copper & zinc combination, copper is a higher Eo value than zinc and is the cathode.  The cathode has a positive charge and is +0.34 volts.

The zinc reaction is reversed to be the oxidation reaction, the anode with a negative charge and is+0.76 volts.

So, the total emf (electromotive force) -- also referred to as cell potential -- is +1.1 volts.

A typical question on quiz or test is to provide a combination and ask if the cell would generate electricity, including a combination that's not spontaneous (totals (-) Eo).

BTW, a student might ask why you don't multiply the total Eo by the coefficients.

One explanation is:

 "It is important to note here that Eo's are intrinsic properties of reactions and, therefore, do not depend on the stoichiometry of the reaction. That means that you DO NOT multiply the Eo of a reaction by the coefficient used to balance the overall redox reaction. "

You can read more at the following page:
http://www.sparknotes.com/chemistry/electrochemistry/galvanic/section2.rhtml

I would photocopy a very minimalistic cell, such as that below and photocopy it as a handout for my students:
Picture
I would have this image on an overhead projector and would use it to determine the information to be determined about an electrochemical cell. The back of the page could have one or two more blank examples for students to practice with.

There is an abbreviated way to represent an electrochemical cell known as "cell notation" -- here's a discussion and a few examples:
Here are some samples of worksheets about Electrochemical Cells:

These pages have answers:
http://chemistryconnections.com/electrochemistry/electrochem.pdf

http://kurtniedenzu.cmswiki.wikispaces.net/file/view/Wkst_echem_09.pdf/203482322/Wkst_echem_09.pdf

The following page could also be used as a quiz:
https://docs.google.com/document/d/11vmGv_OSmQNqF-N_ZDDiHw3x5HKua-G-I-oInGMnVlI/edit?pli=1

A simple lab or demonstration could be using voltmeters and alligator clips (if necessary, borrowed from the Physics department), filter paper cut into strips and saturated with a potassium nitrate solution for the salt bridge, and 100 mL beakers to contain the solution and electrode for each half-reaction.

Each half-reaction would contain an electrode submersed in its solution (e.g. Zn in ZnNO3) and a saturated piece filter paper to act as a salt bridge.  Students could measure the emf of various combinations.  They could also observe how the voltage disappears when the circuit is disconnected by removing the salt bridge.

Here's a lab based on this type of set-up:

http://webs.wofford.edu/splawnbg/Chem_124_files/11_Measuring%20Electrochemical%20Cells%202009.pdf

This lab is a little longer than I'd like, but it is basically the same overview:

http://www.doctortang.com/Honour%20Chemistry%20%28Old%29/Lab%2010%20Electrochemical%20Cells.pdf

Spot plates may not provide enough of the reactants for a good reading.

I appreciate your patience with my blog posting schedule.  I should be able to post about Electrolytic cells this Sunday, 5/18/14.

Check out my lab book "Chemistry on a Budget" at amazon.com:
http://www.amazon.com/Chemistry-Budget-Marjorie-R-Heesemann/dp/0578129159/ref=sr_1_1?s=books&ie=UTF8&qid=1389410170&sr=1-1&keywords=chemistry+on+a+budget

Each lab is presented with two possible report formats -- both labs use the same procedure but each has a different conclusion -- one with 10 questions to be answered as a conclusion, the other with a full laboratory report required.  This gives the teacher the option of what type of report is desired, and each version is designed to be just two pages.  This way the teacher can photocopy just one 2-sided page per student (saves paper).  

*I'd love to hear from you!  Your feedback would really help me to focus on your needs!  There should be a "Contact" form below, or click on the "Contact" tab on the top right of this page.  

Have a good end of the week!

0 Comments

new schedule

5/10/2014

0 Comments

 
Due to various obligations, I will only be posting once a week, including through the summer.  My next post should be Wednesday, 5/14/14 about Electrochemical Cells.  Eventually (I don't know when), I will be moving my posts to Sundays.

I'm very happy that more people are visiting this blog!  Yay!

Check out my lab book "Chemistry on a Budget" at amazon.com:
http://www.amazon.com/Chemistry-Budget-Marjorie-R-Heesemann/dp/0578129159/ref=sr_1_1?s=books&ie=UTF8&qid=1389410170&sr=1-1&keywords=chemistry+on+a+budget

Each lab is presented with two possible report formats -- both labs use the same procedure but each has a different conclusion -- one with 10 questions to be answered as a conclusion, the other with a full laboratory report required.  This gives the teacher the option of what type of report is desired, and each version is designed to be just two pages.  This way the teacher can photocopy just one 2-sided page per student (saves paper).  

*I'd love to hear from you!  Your feedback would really help me to focus on your needs!  There should be a "Contact" form below, or click on the "Contact" tab on the top right of this page.  

Have a good week!
0 Comments

electrochemistry -- balancing redox reactions

5/7/2014

0 Comments

 
Continuing with the topics of Electrochemistry, today I'm going to focus on balancing redox reactions.

Objectives:

1.  Compute the oxidation number of an atom of any element in a pure substance.

2. Apply the half-reaction method to balance redox equations.

I posted information about assigning oxidation numbers in my previous post -- here's a simple list of basics to memorize for your reference:
Picture
Remember, pure elements have an oxidation state of 0 !
Worksheets with practice assigning oxidation numbers are in my 5/4/14 post as well.

It is important to balance the charges exchanged when balancing redox reactions -- one approach is to examine the oxidation and reduction separately, called the half-reaction method.

Here is a simple introductory example:
This next video has a list of steps and goes through a more difficult example:
Here's is a written list of steps and an example (again, a little more difficult):

http://homepage.smc.edu/merlic_jennifer/Chem11/Handouts/Half_Reaction_Method.pdf

This page also has a list of steps on how to approach a redox half-reaction problem:

http://faculty.scottsdalecc.edu/borick/files/2011/05/Balancing-Redox-Reactions1.pdf

Here's a series of links with background notes, a worksheet, and answers:

http://chemistryfouryou.weebly.com/uploads/8/9/2/7/8927138/9.2_balancing_redox.pdf

http://library.vcc.ca/learningcentre/pdf/vcclc/Chem0993-BalancingRedoxReactions2.pdf

This link has several examples but no answers.  :-(
http://www.fieldlocalschools.org/userfiles/1138/Classes/7788/Redox%20Reactions%20Worksheets.pdf

Because I'm focusing on Introductory Chemistry, I only presenting the half-reaction method for balancing redox reactions.

Check out my lab book "Chemistry on a Budget" at amazon.com:
http://www.amazon.com/Chemistry-Budget-Marjorie-R-Heesemann/dp/0578129159/ref=sr_1_1?s=books&ie=UTF8&qid=1389410170&sr=1-1&keywords=chemistry+on+a+budget

Each lab is presented with two possible report formats -- both labs use the same procedure page but each has a different conclusion page -- one with 10 questions to be answered as a conclusion, the other with a full laboratory report required.  This gives the teacher the option of what type of report is desired!  

*I'd love to hear from you!  Your feedback would really help me to focus on your needs!  There should be a "Contact" form below, or click on the "Contact" tab on the top right of this page.  

Have a good end of the week!
0 Comments

electrochemistry -- redox basics

5/4/2014

0 Comments

 
The end of the school year is approaching, so the next topic is Electrochemistry. Today, I'm starting with the basics, and over the next few weeks I'll get into half-reactions, electrochemical and elecrolytic cells.

Objectives:

1. Define oxidation and reduction.

2.  Compute the oxidation number of an atom of any element in a pure substance.

3.  Distinguish between redox and nonredox reactions.

4. Identify the oxidizing and reducing agent in a redox reaction.

According to http://en.wikipedia.org/wiki/Oxidation_state:
"The oxidation state, often called the oxidation number, is an indicator of the degree of oxidation of an atom in a chemical compound. The formal oxidation state is the hypothetical charge that an atom would have if all bonds to atoms of different elements were 100% ionic."

Assigning the oxidation states of all components in a chemical reaction helps determine if oxidation and reduction are occurring.  If oxidation occurs, another substance must be reducing.  One analogy is that of a pitcher throwing a baseball, there must be a catcher for the baseball.

An equation that demonstrates a change in oxidation numbers shows both oxidation and reduction processes, typically shortened to the term "redox" .

By the way, a mnemonic used to remember the movement of electrons in redox is "LEO GER" where the loss of electrons is oxidation and the gain of electrons is reduction.

Another mnemonic is "OIL RIG" where oxidation is loss and reduction is gain.
 
Determining all of the oxidation states in a reaction helps in determining if redox is actually occurring.

Here is a video segment talking about these basics and providing  a little history as well:
He does go through half-reactions and balancing pretty quickly  -- I'll talk about it more in-depth during my next post.

There are several lists of the Rules for Assigning Oxidation Numbers -- here's one:
Picture
Here's a worksheet along with a couple of pages of Rules for Assigning Oxidation Numbers:

http://tmachemistry.wikispaces.com/file/view/Oxidation+Numbers+1.pdf


Here are some more worksheets focusing on assigning oxidation numbers:

http://teacherweb.com/FL/StonemanDouglasHS/ASampson/1st-OXIDATION-NUMBERS-WORKSHEET.pdf

http://www.ylhs.org/apps/download/2/MdrNAknDeUzNgOQNbgs09d0MZ8mTHeEcQhYnatA1FkeyOSEZ.pdf/Worksheet%20-%20assigning%20oxidation%20numbers.pdf

This worksheet also includes answers, and moves on into identifying the oxidizing and reducing agents:

http://www.srvhs.org/Staff/teachers/jleach/CH%208%20Oxidation%20Reduction%20Reactions0001.pdf

In this video, all of the oxidation states are assigned and then what is oxidized and reduced and the corresponding agents can be identified:

His summary of oxidizing and reducing agents is a little confusing -- one way I practiced with my students was to automatically identify what is oxidized/reduced/oxidizing agent/reducing agent and that if you identify one of those parts of the reaction, you can identify the other parts easily.
Here is a PowerPoint presentation that is a helpful introductory lecture to Electrochemistry:

http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=7&sqi=2&ved=0CEsQFjAG&url=http%3A%2F%2Fteachersites.schoolworld.com%2Fwebpages%2FRTauriello%2Ffiles%2Foxidation%2520numbers%2520and%2520redox%2520reactions%2520%28redox%2520part%25201%29.ppt&ei=CP1kU8fBDeissAS18YGQBA&usg=AFQjCNG7qSipACjx-Dfj_SkgCLeu35T4PA

Here are some worksheets identifying what is oxidized/reduced/oxidizing agent/reducing agent:

This worksheet series does get into half-reactions as well -- that will be on the next post!

http://bhhs.bhusd.org/ourpages/auto/2010/6/28/55919701/Chapter%2020%20Worksheet%20Redox.pdf

This worksheet also gets into half-reactions and balancing -- sorry!

http://butane.chem.uiuc.edu/cyerkes/Chem102AEFa07/worksheets/Worksheet%207.pdf

Check out my lab book "Chemistry on a Budget" at amazon.com:
http://www.amazon.com/Chemistry-Budget-Marjorie-R-Heesemann/dp/0578129159/ref=sr_1_1?s=books&ie=UTF8&qid=1389410170&sr=1-1&keywords=chemistry+on+a+budget

Each lab is presented with two possible report formats -- both labs use the same procedure page but each has a different conclusion page -- one with 10 questions to be answered as a conclusion, the other with a full laboratory report required.  This gives the teacher the option of what type of report is desired!  

*I'd love to hear from you!  Your feedback would really help me to focus on your needs!  There should be a "Contact" form below, or click on the "Contact" tab on the top right of this page.  

Have a good week!
0 Comments

    Author

    Marjorie R. Heesemann is a chemistry teacher with 15 years of experience who is now working to develop resources for the Chemistry classroom.

    Archives

    April 2018
    March 2018
    February 2018
    January 2018
    December 2017
    November 2017
    October 2017
    September 2017
    August 2017
    July 2017
    June 2017
    May 2017
    April 2017
    March 2017
    February 2017
    January 2017
    December 2016
    November 2016
    October 2016
    September 2016
    August 2016
    July 2016
    June 2016
    May 2016
    April 2016
    March 2016
    February 2016
    January 2016
    December 2015
    November 2015
    October 2015
    September 2015
    August 2015
    July 2015
    June 2015
    May 2015
    April 2015
    March 2015
    February 2015
    January 2015
    December 2014
    November 2014
    October 2014
    September 2014
    August 2014
    July 2014
    June 2014
    May 2014
    April 2014
    March 2014
    February 2014
    January 2014

    Categories

    All

    RSS Feed

Powered by
✕