VODCast for Solutions to Complex Gas Law Problems

A VODCast has be posted on the Events Calendar on the date Sunday, December 12th, 2010 that has the solutions for the four complex / advanced gas law problems that were given to you early last week. These type of problems are fair game for the test on Tuesday, December 14th, 2010.

Key for Chapters 10 and 11 Test Review Available

On the Events Calendar under the date Saturday, December 11th, 2010, I have posted a pdf file of a key for the Chapters 10 and 11 review that you were given in class. It is a VERY in-depth key that explains in detail the reason for every answer. Since it was based completely on old AP Chemistry test questions, I have also given hints on how the questions are written and the best methods for answering the questions correctly and quickly. Later on today, I will post a VODCast of the solutions for the four higher level gas law problems that you were given in class early last week.

Thermo Questions for Chapter 11

Below are the three questions that you need to answer for tomorrow, Friday, December 10th, 2010. There is also the Power Point file on the Events Calendar. This will be graded at the beginning of class on the due date.

Corrections and Extensions

First, it was brought to my attention that I had a couple of wrong answers on the Organic Chemistry Practice Test. I named the number of carbons wrong in numbers 16 and 17. I counted seven, but used the base name Hex- instead of Hept- like I should have. I have made corrections and have posted the corrected version of the key on the Events Calendar.

Also, I am going to extend the due date of the Organic Chemistry independent study until next Monday, December 6th. I really want as many people to complete the independent study as possible. It is a minor part of the AP Chemistry exam, but any little bit will help to get a passing score for you. I will also extend the Jmol extra credit until next Monday.

I have posted the Chapter 10 homework on WebAssign. Please keep up on the assignments. Make it a goal to do five problems a night starting tomorrow night. This will make the homework not such a burden to you right before the exam. Also, you will be practicing while I am lecturing on the material. Please make sure to view the VODCasts posted on the dates Nov. 29th and 30th, and Dec. 1st and 2nd. Like I said in class today, I will lecture the material, but it will be at lightning speed. I want to use the class time for demonstrations and concept discussions. The VODCasts give examples of most of the problems that you will see on WebAssign. Anything not covered by the VODCasts, I will lecture on in class.

The final test/exam of the semester will be the Tuesday before final exams start. The test will cover all of Chapter 10 and most / if not all of Chapter 11. We should be done with Chapter 10 by this upcoming Friday. We will spend next week on Chapter 11. What material from Chapter 11 that can be covered from Monday to Friday of next week will be on the exam. You will have access to a review for the test beginning late next week and a key will be supplied. Monday, December 13th will be used as a review for the test on Tuesday.

On finals day, we will go over the final test of the semester. We will complete a lab on that day. The lab will deal with the concept of chromotography. I will ask that you complete the lab write-up that night (Thursday, December 16th) and turn the lab in to me the next day before you leave on winter break.

EXTRA CREDIT! EXTRA CREDIT!

As promised, a true extra credit opportunity. This will be worth 15 points towards your homework grade. Your mission, if you choose to accept it, will be to download a virtual molecule building program from the internet and use the program to build a virtual molecule. If you try to build the molecule that I designate for you and email the file to me, you will get 10 of the possible 15 points. To get the remaining 5 of the 15 points, the molecule must be built correctly. If you Google the molecule that I designate for you, you should be able to find an image and just replicate that image. My goal for this project is not for you to build the molecule correctly (though I would like that to happen), but rather that you familiarize yourself with the software.

The software is called Jmol, and it is freeware. Use the link to go to the site and follow the directions on how to download the software. You may need a decompression program to extract the files from a folder. I have made a short PODCast how to download the program and use it. It is labeled Jmol Demo and can be found on the date November 25th on the Events Calendar. Please email the completed file to me at cbrueckner@lps.k12.co.us.

Below are the designations for what organic compound you are to build.

• If your last name starts with "A" through "G" - build the compound cis-difluoroethene.
• If your last name starts with "H" through "L" - build the compound 2-Butene.
• If your last name starts with "M" through "P" - build the compound Propyne.
• If your last name starts with "S" - build the compound Butanol. **If your last name starts with "Si" and you have a XY chromosome, you must build Isobutanol. But if your last name starts with "Si" and have a XX chromosome, you will still build Butanol. If the "Si's" of the class do not understand what I mean, you better look up chromosomes.
• If your last name starts with "T" through "Z" - build the compound trans-difluoroethene.

To all in the class. If anyone can build Methylbenzene and send me the file, it will be worth another 5 points extra credit towards your homework grade. Good luck and look back at the blog this weekend for some other information that I will be putting out about the chapters in the book that will be covered after the Thanksgiving break.

Organic Chemistry Test Posted

I finished the Organic Chemistry Test and it has been posted on the Events Calendar under the date Wednesday, November 24th. The test will be worth a total of 29 points that will go towards your ASSESSMENT (60% OF YOUR GRADE) category. This is a great opportunity for everyone to have a really good test score to help your overall grade.

When answering the written questions: (1) make sure to define any terms that you may use; (2) when comparing molecules, make sure to highlight similarities and differences between the molecules; and (3) reference any figures that you may draw to represent the compound(s) in question.

The test is a little different than the practice test. In the test, I have taken some liberties to incorporate concepts from past units into organic chemistry. One is polarity of molecules. A polar molecule is asymmetrical in relation to dipoles within the molecule. A non-polar molecule is symmetrical in relation to dipoles within the molecule. I have also incorporated chemical reactions, like the AP Chemistry test will do. Remember, most organic compounds are hydrocarbons. You need to know what is produced when a hydrocarbon combusts.

Good luck and email me if you have any questions.

p.s. Look tomorrow at the blog for a true extra credit opportunity.

Solutions Movie Available and a Change

I just wanted to let everyone know that the solutions are available on the Events Calendar under the date November 23rd. Sorry that I did not get it on the calendar yesterday, but the movie took a lot longer to make than I expected. I hope to have the actual test for the organics independent study posted later today. If not, it will be very early on Thursday morning, November 25th. You can watch the Macy's parade and some football while you do your test. :) Please email me if you have any questions.

There are two changes to the practice test that I made. If you downloaded the practice test prior to 2:00 pm yesterday, you will have to make changes to two problems, #30 and #31.

• #30 was changed from 5-Bromo-1-Pentene to 5-Bromo-1-Pentyne
• #31 was changed from cis-3-Hexyne to cis-3-Hexene

If you downloaded the file yesterday late in the afternoon or last night, the correction was already made on the practice test. The file on the calendar now has the change in it.

HELP FOR YOUR GRADE! (If you want it.)

I hope that everyone is having a good break so far. As I promised in class on Friday, November 19th, I have a couple of ways to help you improve your grade. Not all of the ways are extra credit like I wrote on the board, but it is even better! (For your grade that is, not you.)

First, I am going to offer an opportunity for you to complete a independent study unit on Organic Chemistry, which is Chapter 25 in your book. This will be a short, but complete unit on the chemistry of carbon. AP Chemistry is a course designed to be equivalent to an upper level college freshman chemistry course. Therefore, after the successful completion of freshman chemistry, a chemistry, biology, pre-med, or chemical engineering major would move on to a year long course in organic chemistry. The branch of organic chemistry in the chemistry tree is the largest. It is the chemistry that is the back-bone of the pharmaceutical industry, petroleum industry, and almost everything you buy without a prescription at the corner drugstore. Thousands of new chemicals are discovered every year and the vast majority of them are organic compounds. It is incredibly important, so a very minor amount of information known about it will be a benefit to you. This would help as you possibly move on to AP Biology, or get a 4 or 5 on the AP Chemistry exam and move right into organic chemistry in your first year of college, or most important for right now, see a couple of questions pertaining to organic chemistry on the AP Chemistry exam. I do not cover this material in class because it historically is a very minor part of the exam and there just is not enough time to cover everything during the course, but also enough of the exam that it could be the difference for some to passing the exam or moving to the 4 and 5 region of the exam.

THIS INDEPENDENT STUDY UNIT IS OPTIONAL AND NOT REQUIRED FOR THE COURSE. IT IS DESIGNED TO BE AN ENRICHMENT TO THE COURSE AND A VERY MINOR PORTION OF THE AP CHEMISTRY EXAM.

The unit will consist of you reading the chapter and studying the Chapter 25 Power Point that is available on the class Events Calendar, completing a practice test, and then finally completing a written take home quiz that will turned into me at the beginning of class Monday, November 29th, 2010. This take home quiz will be 20 questions. This is an opportunity for you to add a really good score to your assessment grade. It will be open book, open note, open internet, and open study buddy if you choose. I would suggest that everyone who wants to improve his or her grade take this opportunity and also those that are really serious about scoring well on the AP Chemistry test. The test is the only part of this independent unit of study that will be graded.

• The Chapter 25 Power Point can be found on the Events Calendar of my AP Chemistry web-page under the date of Sunday, November 21st, 2010. I have eliminated about 1/3 of the chapter from the Power Point. The independent study will focus on the classifying and naming of organic compounds and certain functional groups. Also, molecular geometry, bond angles, and hybridization that was learned in the previous unit will be applied to organic molecules.
• The Chapter 25 practice exam will be a .pdf file found on the Events Calendar under the date Monday, November 22nd, 2010. The practice test consists of 32 questions. For each question, page numbers in the book have been given to guide you to the area in the book that you will need to read and study to answer the question.
• A VODCast of all of the solutions to the practice test will be posted to the Events Calendar under the date of Tuesday, November 23rd, 2010. It will be more than just answers. I will use the practice test as an opportunity to teach a deeper understanding of the concepts associated with each question.
• On Wednesday, November 24th, 2010, the actual take home quiz will be posted on the Events Calendar as a .pdf file. You will need to print the quiz and complete it and be ready to turn in at the beginning of class, Monday, November 29th, 2010.

Below are links to four video resources that I found on the web that could be of use to you as you complete this independent unit of study.

• A VODCast/Power Point from Professor Chuck Wight of The University of Utah. This was designed for a first year chemistry course (like AP Chemistry) at UU, so it fits our needs quite well. Please keep in mind that the take home quiz will focus on material covered in the practice test, so some of what is presented you will not be held accountable for. Prof. Wight covers many functional groups that I will not be focussing on. The functional groups that I will hold you accountable for are alcohols, amines, halogens, and carboxylic acids. These four and all of the other functional groups can be found on page 1071 of your book. This YouTube video has a running time of almost eight minutes.
• The second VODCast that you can watch covers specifically how to name organic compounds. The naming system is governed by an international organization called IUPAC. You may see this acronym as you read the chapter or look on the internet. The acronym stands for International Union of Pure and Applied Chemistry. This YouTube video has a running time of just over nine minutes.
• The third internet resource that you can watch is a fairly humorous and catchy tune about naming organic compounds. There is a video accompanying the song. It is a good source to really condense many of the naming concepts for organic compounds. This YouTube video has a running time of two minutes and forty seconds.
• The fourth internet resource that I have to offer is a very short video that shows the resonance structure creation of an organic compound benzene. It does a very good job of illustrating the overlap of un-hybridized "p" orbitals to form the "pi" portion of a double covalent bond. You will read quite a bit about benzene and the delocalized bonds within the molecule. This video, I hope, gives you a better understanding of that concept.
• The fifth internet resource is a silly little video and song about benzene. Watch and get a little in-depth information about a very common substance found in industry.

Finally, you will have a true extra credit opportunity this week. You will be asked to download and use a molecular modeling software called Jmol. Use the link on Jmol to go to the site and download the software now if you want. I will have a VODCast available either Wednesday or Thursday of this week on how to install and use the software. Look back to the blog later this week on specifics of what you need to do to earn the extra credit.

I will be checking my school email periodically over the break, so email me if you have any questions. Also, you do have my cell phone number, so please feel free to call if you need any assistance.

Chapters 8, 9, and 24 Review

Below this written is a key for all of the questions /problems presented in the review for the Chapters 8, 9, and 24 test. All of the concepts on the test are not covered by the review packet. I will list the topics not covered in the review packet so you can look at other materials from the unit of study. The test will consist of 35 multiple choice questions and 5 short answer questions. You will be supplied a periodic table (the one given for the AP Chemistry exam) and I will give you a electronegativity table, though one would not be supplied on the AP Chemistry exam. You will also be able to use a calculator.

I have supplied more information than what is needed in the answers to the key below. I was more in-depth than what would be needed on the exam because I wanted to use the study guide and key as one last teaching tool. When answering an AP Chemistry free response question: (1) Do exactly what is asked to do. (Draw a Lewis structure, etc.) (2) Make sure to compare and contrast if asked to do so. (3) Any term used in the answer should be defined.

WHAT TO STUDY

1. Know how to define (non-polar) covalent, polar covalent, and ionic bonds and understand the mechanisms of how each is made.
2. You need to know from memory all parent geometries, molecular geometries, and bond angles. Know the criteria for each.
3. Know the concept of lattice energy and that the magnitude of lattice energy is dependent upon the magnitudes of the ion charges and the distance between the nucleus of both ions in the bond. For a large lattice energy, large charge magnitudes and small ion distances are needed. For a smaller lattice energy, small charge magnitudes and large ion distances are needed. L.E.=k(Q1Q2)/d.
4. Know all criteria for hybridized orbitals. On a previous blog post, all of the criteria and applications were written out.
5. Know how to determine the enthalpy (heat) of a reaction from the energy inputs (i.e. heat of sublimation, bond energy, ionization energy, etc.) and energy outputs (electron affinity, lattice energy). If energy inputs exceed energy outputs, a endothermic reaction will occur. If energy outputs exceed energy inputs, a exothermic reaction will occur.
6. Know how to choose the most plausible Lewis structure based upon formal charge. Zeros are preferred and the more electronegative element should be a negative number is not zero. Also, all formal charges must add up to the total charge of the molecule.
7. Know the basic concept of isomers. This is covered in its most basic form on page 1026 of your book at the very beginning of section 24.4. This concept is covered in the review from the year 1994, question #43. An isomer is a molecular formula that can have more than one Lewis structure that works for the number of atoms in the molecule. This is not to be confused with resonance structure, which is just the moving of a double or triple bond. This is completely different positions of atoms within the molecule with different types of bonds to achieve the different atom positions. I have given an explanation on the review.
8. Know how to define and recognize a Lewis acid and a Lewis base.
9. Know the rule to determine the coordination number of a Lewis acid is to double the oxidation (charge) number. The coordination number will be the number of ligands (Lewis bases) that will surround the Lewis acid (metal ion) in the middle of the complex ion.
10. Know the types of hybridization for a metal that are needed for different coordination numbers.
11. Know the basic naming system of complex ions.
12. Be able to write a net ionic reaction for the formation of a complex ion.

Correction to VSEPR Lab

The correction to the 2nd VSEPR lab has been made and is posted in the same place on the Events calendar as the original. The last slide was changed from sulfur monofluorine tetrahydride (SFH4) to iodine monofluorine tetrahydride (IFH4). Also, if the file for the Power Point becomes too large to send via email, please bring the file to me on a CD or a Flash drive. Please come and see me if you have any questions about the lab.

The question #5 from the Chapter 8 WebAssign has been removed due to difficulties completing the problem.

On Wednesday, you will be receiving an optional review assignment for the unit exam which will be this upcoming Friday, November 19th. I will try and have a podcast of the solutions posted so you can assess your comprehension of the material on the unit.

VSEPR Lab

You were given the VSEPR lab today in class. The lab will be due next Thursday, November 18th, 2010. The lab that you need to access is posted on the Events Calendar on the AP Chemistry web-site. VSEPR is an acronym for Valence Shell Electron Pair Repulsion. It is the repulsion of the electrons that create the geometric angles between the bonding and non-bonding ligands. Remember, non-bonding ligands repel more than bonding ligands. That is why the bond angles decrease as bonding ligands become non-bonding ligands within a particular type of parent geometry. Remember on the parent geometry trigonal bypyramidal, the equatorial bonding ligands transform to non-bonding ligands first because of the greater bond angles (120^o vs 90^0) allows for more space between the non-bonding ligands. (Non-bonding ligands repel more than bonding ligands.)

Molecular polarity - is a molecule symmetrical (same charge distribution all around the molecule) or asymmetrical (charge distribution is unequal around the molecule)? Symmetrical is a non-polar molecule and asymmetrical is polar. When you build your molecules, any difference in color for pipe cleaners used will cause the molecule to be asymmetrical, thus polar.

Please see me if you have any questions concerning the lab or concepts needed for the lab.

Take-Home-Quiz and Hybridization Recap

Below are two images of Power Point slides that have the questions that need to be answered for tomorrow, Friday, November 12th, 2010. Please have your solutions / answers to the problems ready to turn in at the beginning of class.

I would like to go through a quick recap of hybridization for bonding.

• A single bond always involves only a sigma bond. A sigma bond is between two hybridized orbitals or a hybridized orbital with a non-hybridized 1s orbital of a hydrogen atom.
• A double bond always involves a sigma bond and pi bond. The pi bond originates from two non-hybridized p orbitals overlapping.
• A triple bond always involves a sigma bond and two pi bonds.
• Ligands are either covalent bonds or non-bonding electron pairs. A single covalent bond, double covalent bond, or triple covalent bond are all considered one ligand.
• sp^3 hybridization is required when four ligands surround an atom. The hybridized orbitals can be used for sigma bonds or to hold non-bonding electron pairs.
• sp^2 hybridization is required when three ligands surround an atom. The hybridized orbitals can be used for sigma bonds or to hold non-bonding electron pairs.
• sp hybridization is required when two ligands surround an atom. The hybridized orbitals can be used for sigma bonds or to hold non-bonding electron pairs.

General Information

The WebAssign is up for chapter 8.

Do it for the band!

For those of you that were in class today and those of you that were not, this post has something for all of you. First, a VodCast showing the solution to the problem given in class on Thursday, October 21st has a link and file on today's date on the AP Chemistry calendar. You are asked to view the solution to problem #2 from the 2007 AP Chemistry Test Form B. To offer up extra incentive to view the Vodcast, there will be a quiz given the last 20 minutes of class on Monday, October 25th over the material covered on the 1999 and 2007 test. The topics covered will be the Bohr model of the atom and calculations associated with the Bohr model. The topic of bond energy will also be incorperated. To give those of you a little prize for reading the blog, any student that writes "YABBA-DABBA-DOO" across the top of his or her quiz will get extra credit on the quiz.

Also on the calendar is a link and file for the Power Point for Chapter 6 if you would like to download it. I would suggest that everyone read sections 4 through 8 of Chapter 6. Hopefully everyone has some recall of electron configurations from the 1st year course.

Finally, I want everyone on Saturday to celebrate the greatest of little known holidays. On Saturday, October (10th month of the year) 23rd, from 6.02 a.m. to 6.02 p.m., please join me in celebrating MOLE DAY!! We will have a belated celebration on Monday. I will bring treats to class. Have a good weekend.

Gravimetric-Titration Lab

So you can solve for a percent error / difference on your lab, the concentration of barium hydroxide was 0.0723 M. Also, in case you forgot to write down the molarity of the sulfuric acid solution, the concentration was 0.119 M. Your lab reports will be due on Tuesday, October 19th, 2010. Remember, on Monday, October 18th, you will be having a quiz over the analysis and calculations associated with the lab.

Calorimetry Solution and Two More Problems

Below are the two problems (Calorimetry #1 and #2) that I would liked solved before class tomorrow, Thursday, October 7th, 2010. Below the two problems is the calorimetry problem presented in class and the solution to that problem.

Mole Ratio Lab Practice Quiz Key and Chapter 5

A .pdf file of the a key for the practice mole ratio lab quiz has been put on the AP Chemistry Events Calendar under today's date (9/29/2010). On tomorrow's date (9/30/2010), I have put the Power Point file for Chapter 5. You may want to print it off so you have notes to go from as I lecture in class. I will be utilizing it in class. We will be skipping much of Sections 5.1 through 5.3. Much of that material will be covered in Chapter 19 next spring.

You will be having your quiz over the Mole Ratio Lab analysis first thing tomorrow. Please see me if you have any questions about seperating the data or doing the analysis / intersection determination on your calculator.

Remember, on Friday morning, October 1st, there will be the remedial session to earn back 1/2 of your points from the Chapter 4 test. The remedial session will be in room #327 from 6:30 am to 7:15 am.

Redox Lab Report and Chapter 4 Test Results / News

I will first address the results of the Chapter 4 Test. The average for the test was a 60%. The median for the test was also 60%. This is not out of the historical norm for this test. You may be asking yourself, "Why give the test if you have such poor averages?" I will reply that I want to give a very challenging test for all participants. I do not want a bunch of perfect scores. If I did have that, the test is not very challenging. On this exam, there was a high score of 17 out of 20 amongst the 29 students who took the exam. Now, to make things fair for all party's involved, I am going to curve this exam. In Infinite Campus, I am going to make this exam worth 40 points. (There were 20 questions, so I am going to double the points.) I am going to add 4 points to your total points earned out of 40. This is a 10% curve, which will bring the average up to 70%, which is a low "C", which is average. I know many of you would disagree with me and call a "C" failing, but that is in your own little world, not mine and the rest of human civilization. :)

But wait just one minute kids! I have an even better deal for you! If you choose, you can earn back one half (1/2) of your points. I am going to have another remedial session for those students who did not fair very well. If you attend the 45 minute remedial session next Friday morning (Oct. 1st) from 6:30 a.m. to 7:15 a.m., I will give you back 1/2 of your points that you missed. For many of you, this will exceed the 4 points that the curve offers. So, if you miss any more than 8 points, you will earn more than just taking the curve. For clarification, a 4 point curve will be given to everyone. Anyone wanting to attend the remedial session can earn more. I will not be including these test scores in the first six week grades because you can earn different point values if you choose.

Just to let you know, this will not be the last time a very low test average will be attained by the class. To make it challenging for all participants in the class, the tests need to be difficult. For context, I want to share with you a little story from my wife, the Lovely Mrs. Brueckner. When I told her of the complaining that many AP Chemistry students were taking part in after a particularly hard exam, she told me to tell them (the students) to "suck it up and live with it." The Lovely Mrs. Brueckner attended the University of California at Davis, which is a very renowned science school because of the Veterinary and Medical schools that are part of the university. Mrs. Brueckner was a cellular physiology major (Mrs. Brueckner is much smarter than Mr. Brueckner), which is major league science if you did not know. Anyway, Mrs. Brueckner shared that while at Cal Davis and taking organic chemistry, one test average in the class was in the mid-30% range. She attained a 65%. Her 65% became an "A". So the moral of the story is that it is not your actual score that is important, but rather, what was your score relative to everyone else. I had similiar experiences in college. You will be getting your exams back on Monday, September 27th.

On Monday, September 27th, your Oxidation / Reduction Titration Lab write-up will be due. There will be a different take on how I want the SEE's and Conclusion addressed in the lab report. Most people do fine in terms of attaining the 3% hydrogen peroxide value. Therefore, there is no reason to make-up SEE's, unless one trial really warrants having a SEE written about it due to a procedural gaffe during the lab. Otherwise, there was one systematic SEE that everyone has. It is #2 of the SEE's section. Make sure that you address how the addition of the inhibator in the hydrogen peroxide solution affects your calculated value for the percent hydrogen peroxide in the solution. Does it cause it to be higher than what it actually is? Does it cause it to be lower than what it actually is? Please give a well thought out reason why.

Your conclusion just needs to address all six questions listed in that section of the lab. Please write in complete sentences.

You will also getting back your quizzes based upon the Redox Titration lab on Monday. Also, on Monday we will be doing a pre-lab activity for a lab that will be completed on Tuesday, September 28th. Finally, another little remidner, the WebAssign work for Chapter 4 is also due Monday, September 27th, 2010. Have a good weekend.

New VodCast - Balancing Redox Reactions

I added a new VodCast. It is a .mov file, so it can be played with Quicktime. It can be found on the AP Chemistry calendar on the class web-site under the date of September 21st, 2010. It is problem 14(d) from WebAssign and deals with balancing the reaction in a basic environment.

Remember, we are meeting tomorrow (Wednesday, September 22nd) in the big computer lab in the library. We will be reviewing for the Chapter 4 test (which you will take on Friday, September 24th) and the Redox Titration Lab quiz (which you will take on Thursday, September 23rd.). You will have the opportunity to work on WebAssign during the period.

Redox Titration Lab: Balanced Equations_Concentration Calculations

Below are the images from the Power Point presentation shown in class today. Please use this as a guide on how to do all calculations for the lab. You will be required to do calculations like this on a quiz that will be given Thursday, September 23rd, 2010. Also, I will try and do a VodCast of the problem 14 (d) from WebAssign. I will post it under today's date (9/20) as a .mov file so can be played on Quicktime.

AP Level Free Response Question

After much debate in class today, we will have the solubility / ion concentration quiz tomorrow. The two practice problems on the Chapter 4 blog are extra practice for tomorrow's quiz. Also, on the Event Calendar on today's date (9/16) I have put the video file for the solution of the first practice problem. It is a .mov file, so you will need Quicktime to play it.

Please solve the problem below. You will be graded on your results, so it needs to be completed before class starts on Friday, September 17th, 2010. This problem is on par with any problem that you would see on the AP Chemistry test, free response section. Good luck.

Solubility and Ion Concentration W/S

Below is the solution for #8 of the Common Ion, Precipitate and Concentration worksheet. There will be a quiz over a problem like the ones you performed on this worksheet on Thursday, September 16th, 2010. Beginning tomorrow (Tuesday, 9/14), under Chapter 4 on the AP Chemistry web-page, there will be two more practice problems for you. Practice problem #1 will have a solution posted on TeacherTube and practice problem #2 will have just the answers. The quiz will be going in the homework section of your grade.

Chapter 3 Quiz Results

Today everyone who completed the Chapter 3 Quiz was shown his or her results. Many individuals did quite well. Of the 29 quizzes scored, 6 (21% of tests) received a perfect score of 23 out of 23. On the opposite end of the spectrum, there were way too many scores that were low D's and F's. Of the 29 quizzes scored, 8 (28% of tests) scored 61% or lower. This is not acceptable since this material is mostly review of material from the first year chemistry course taken as a pre-requisite for AP Chemistry.

Below is a summary of the statistics from the quiz. I have broken the values into three categories: (1) Overall results (2) Junior results and (3) Sophomore results. I want to discuss a disturbing trend that I saw, that is why the two classes (years) were separated.

________Overal results__ Junior results __Sophomore results
Average: __77.0% __________62.6% __________88.3%
Median:___ 82.6%_________ 60.9%___________87.0%

As you can see, the juniors in the class (13 of the 29 tests) underperformed by a large margin when compared to the sophomores (16 of the 29 tests). I can propose one reason for the disparityin the scores.

• For most of the sophomores, they took the pre-requisite course last year before entering AP Chemistry this year. For most of the juniors, they are one plus year removed from the pre-requisite course. This is a possible reason for the disparity, but not an excuse. There were a number of juniors that did very well on the test.

If you were an average freshman sitting in 1st year chemistry up at CU Boulder, most likely you would have taken high school chemistry your junior year of high school. Thus, the average freshman enrolled in first year chemistry at CU Boulder is also two years removed from the first time he or she was first introduced to chemistry. You may have to work a little harder at the review of the material because it is not fresh in your memory. You at one point were proficient at this material because you earned a good enough grade to take this course. You have shown in the past that you have the ability, you just need to sharpen those skills.

No matter how you did on the first assessment of the year, I would like you think about the following points and did you attempt the following during the chapter to be successful.

• Did you read the chapter, even though you were not specifically told to do so? This is a trait that is incredibly necessary for learning high level (college level) material like you are doing now.
• Did you download the PowerPoint file associated with Chapter 3 from the AP Chemistry calender associated with the AP Chemistry webpage? The PowerPoint is a good summary of the material covered in the chapter and offers good examples.
• Did you consistenly work on WebAssign throughout the chapter? The due date for WebAssign work is always one day after the unit assessment, but that does not mean that you should wait until the very end to do the homework. Your homework is your studying, and waiting till the very end to do the work to test proficiency is not productive at all. Worse yet, doing the majority of the work after the exam is really of no point, yet I had reports of students doing this.
• Did you look at my webpage and go to the Chapters section to view the Vodcasts made for the chapter? This could be of some help because both Vodcasts for the chapter covered major topics covered by the quiz.
• Did you go to the AP Chemistry calendar to download the solutions to the old AP Chemistry problems used as review for the quiz. We did go over the solutions in class, but did you study the problems and solutions outside of class?
• DID YOU SEEK OUT EXTRA HELP IF YOU DID NOT UNDERSTAND A CONCEPT? This is the most important and most effective intervention for yourself. It is your responsibility to insure that you know and understand the material. I will give you opportunities to assess you level of comprehension (homework and quizzes), but you need to seek out help if you do not understand the material. Coming in to see me on an off hour is not your only means of getting help. You can email me a question. If I get enough questions on the same subject or problem, I can address it in class for everyone or address it through a Vodcast. If it is a question specific only to you, I can email you back a response. I gave everyone my cell phone number and have had students text me a question. These are all means of getting help for yourself.

Since this was the first assessment of the semester and some of you were maybe taken by surprise in terms of the depth of the material covered and the fast pace of the course, I am going to offer you the opportunity to earn back one half (1/2) of the points that you missed on the quiz. To do so, you must complete a CHAPTER 3 REMEDIAL ASSIGNMENT on WebAssign. This will be due at midnight, Tuesday, September 7th, 2010. Second, from 2:25 pm to 3:15 pm, Tuesday, September 7th, 2010, you must attend a remedial session in room #327 to go over two new AP Chemistry free response questions. Therefore, if you need to make arrangements for a ride from school or make plans with a coach or sponsor to be late for practice or an event, please make the arrangement. This is a one time deal and no exceptions will be made.

Review for the Chapter 3 Exam

On the events calendar for August 31st, I have placed the file (Power Point) for the solutions to the three old AP Chemistry problems that we have been using as our prime review for the Chapter 3 exam that you will take on Thursday, September 2nd, 2010. Some of the solutions are different than what we performed in class, but that is o.k. There is usually more than one way to solve a problem. Remember, tomorrow, we will be in the computer lab in the library. You can use the time to review and work on WebAssign. Have a good night.

Schedule for the week of 8/30-9/3

I just want to give you some insight to the schedule for the week. Tomorrow (Tuesday, 8/31) we will work on the review packet in class of old AP problems. This will be your review for the exam, which will be all written and consist of old AP problems. You may be given parts to the question on the exam that we have not covered yet. I will supply any information to those parts of the test that you will need to use later in the problem. This is just like the review that I gave you. Wednesday is a late start day, so I am going to give you the time to work in class. I will try and supply computers so you can log onto WebAssign and work on your homework. Thursday will be the exam. I hope to have the tests graded by Friday and we can go over them. I will make the Chapter 3 WebAssign due on Saturday, Sept. 4th to ensure that you have the full day after the exam to finish any remaining problems.

GRADES HAVE BEEN UPDATED!!!

I have just updated grades. Some individuals are missing minor assignments (like the signed Lab Safety Contract and Class Policies and Procedures), but because there are very few grades to buffer a bad grade, those individuals have very poor (I'm talkin' "F"!!) grades. Please look at your grade and get the required material to me. The Lab Safety Contracts and Class Policies and Procedures can be found on my teacher pages. I think that activities start taking grade reports this Wednesday for eligibility, so the sooner the better for rectifying the situation.

Copper (?) Iodide Lab Write-Up Due Tomorrow & Preparation

Remember, that tomorrow your lab first write-up for the year is due. Just as we discussed in class, you are not only doing the write-up for a grade in may class, but you are also auditioning for a college or university to receive lab credit if you end up passing the AP Chemistry test next spring. My big area of emphasis on the lab report will be the SEE's and the conclusion. Please make sure that your SEE's address situations that are plausible to your results. If you are overly generic, be prepared to receive no points for your SEE's portion of the report. If you are very specific in your plausible explanation, but contradict your findings, you will receive some credit. So it is better to be intricate and misguided than generic and not address anything of substance. The conclusion must address if the theory was met. Remember, you only have two choices for a plausible formula for copper (I or II) and iodide. Please also include a statement on how you would improve the lab. Just like any other report for any other class, you may want someone to read it for you and critique your work.

In the Chapters portion of my web page, I have posted two links for Vodcasts (new term, catchy, isn't it??) One is for empirical formula determination through combustion analysis and the other is how to determine a limiting and excess reactant. Before tomorrow, (Monday, 8/30), please watch the video on how to determine limiting and excess reactants as a refresher. I will cover the material quite quickly, so the Vodcast will allow you to review / learn at your own pace.

Finally, a AP Chemistry student emailed me with a helpful hint for WebAssign and entering scientific notation numbers. If for some reason (this is a random example) you needed to type Avogadro's number into WebAssign, instead of 6.02 x 10^23, you need to type it in just like it would appear as an answer on your graphing calculator: 6.02E23. If you had a small decimal number, you would type (example): 3.87E-7. Remember to keep plugging away at the WebAssign work. We will probably have a test later this week, so the work will probably need to be done by Friday. Also, your will be getting a review packet tomorrow (Monday, 8/30) in class and I will require the answers to be reported on WebAssign PRIOR TO THE CHAPTER 3 EXAM.

Empirical Formula Determination Through Combustion Reactions and Extra Credit Opportunity

Please complete the problem shown below. Have the solution ready to submit at the beginning of class on Friday, August 26th, 2010. To save time and effort on the problem, notice that the measured values are reported in milligrams. Therefore, feel free to work in the unit of millimole. The ratios all remain the same.

Also, if you would like 10 points extra credit towards your homework grade, bring in a 4-pack of AAA batteries. I will stockpile the batteries and if you need batteries for your calculator at any point this year, you can take a pack from the stockpile.

At the end of class today, there was a queston of what to do with decimals (fractions) once the moles of each element in the compound have been divided by the lowest mole value when determining an empirical formula. If a value is rougly nine tenths (X.9) or one tenth (X.1), then feel free to round up (X.9) or round down (X.1). For other decimals or fractions, use the examples below for how to convert the fraction to a whole number. Remember, elements combine in small whole numbers. **The use of "X" "Y" and "Z" are generic to represent any element.

• 1/2 --> (X .5)x2 --> {Example (Y2Z3.5 )2 --> Y4Z7}
• 1/3 --> (X .33)x3 --> {Example (Y1.33Z1)3 --> Y4Z3}
• 1/4 --> (X .25)x4 --> {Example (Y1.25Z1)4 --> Y5Z4}
• 1/5 --> (X .2)x5 --> {Example (Y1Z3.2)5 --> Y5Z16}
• 2/3 --> (X .67)x3 --> {Example (Y1Z2.67)3 --> Y3Z8}

The fractions represented above are the most common (if not only) fractions you will encounter when doing an empirical formula determination.

Game Day Tomorrow!!

Tomorrow is the first lab of the year. If you will allow me to make an analogy, laboratory day to a chemistry student is like game day to an athlete. Just like the game is the reason for all of the practice that an athlete endures, laboratory work is the reason for learning all of the theory during lecture. You are going to "hopefully" prove all of the theory correct.

Your homework for this evening was to finish the pre-lab question pertaining to the second lab scenario given. Does the the empirical formula of the copper and iodine compound change if the atmospheric pressure changes? We will go over the solution at the beginning of class tomorrow. Remember, keep working on the Chapter 3 WebAssignment.

Beginning of Chapter 3

It is suggested that you read the first five sections of Chapter 3. Today, we covered reactions (writing and balancing), molar (atomic) mass determination of compounds, and simple mole conversions. You should be able to complete through #5 on the WebAssign assignment for Chapter 3. I have set the due date to Monday, September 13th. We will finish Chapter 3 well before that date, so the due date will change to one day after the Chapter 3 test. Also, we will be incorporating old AP Chemistry test written problems into Chapter 3. I will be creating another assignment for the answers to those problems.

Tomorrow, you will be taking the 20 question (true / false) safety quiz. This needs to be completed prior to doing the first lab of the year. We will be doing a pre-lab activity tomorrow over how to determine an empirical formula. On Wednesday, 8/25/2010, we will be performing our first lab of the semester. I will also be going over lab reports tomorrow. PDF files of the lab and the lab report format can be found on the AP Chemistry calendar under the date of 8/24/2010.

Please keep your questions coming via email so I can make of plan of what questions need to be addressed prior to class starting.

Nuclear Reactions (Transmutations)

The last two problems in the Chapter 2 assignment has to do with material presented in Chapter 21 of the book. The questions cover sections 21.1 through 21.3, which deals with radioactive decay of isotopes. It would be a good idea to read over those three sections. Also, if you go to the AP Chemistry calendar, there is a link on August 20th for a Power Point that covers the material covered in the three sections of Chapter 21.

I have also supplied a link for a short movie (9 minutes) on YouTube that covers the basics of nuclear decays / reactions. It is old, but does cover all of the basic points of nuclear transmutation / decay very well. Keep the questions coming via email if any of the questions from WebAssign give you problems.

HOLD THE PHONES!! STOP THE PRESSES!! I HAVE FIGURED OUT HOW TO MAKE A QUESTION THAT STUDENTS CAN ANSWER ON WEBASSIGN!! O.k., it is not that big of a deal, but I did figure out how to make an answer block for questions #16 and #17 on the Chapter 2 WebAssign homework. Cross your fingers and hope that it works.

Mass Spectrometer and Associated Material

Click on the link for the virtual mass spectrometer demonstration if you would like to see how a "mass spec" operates.

A link to the Average Atomic Mass / Percent Abundance worksheet is on the AP Chemistry calendar for August 19th if you need another copy. We will finish the percent abundance practice problem first thing in class tomorrow. I will be requiring that you put your answers to questions #16 and #17 on the WebAssign chapter 2 assignment. Please wait to do so until I have configured the site to take the answers and grade them. Also, because I have added more problems to the chapter 2 assignment, I have extended the due date to Tuesday, August 24rth, 2010.

Chapter 2 Power Point Available

If you would like to download a Power Point file for chapter 2 in the book, one is available.

• go to my teacher page on the HHS site (Brueckner, Corey)
• go into the AP Chemistry page
• click on AP Chemistry calendars
• on Tuesday, August 17th is the link to the file

The first 30 or so slides deal with material covered in the first year course about the evolution of the atomic model. This material will not be covered. The last half of the presentation deals with the material from chapter 2 that is covered in the WebAssign homework. It does a very good job of covering types of compounds, naming of compounds, and writing compound formulas. It is suggested that you work on problems 1 through 9 in WebAssign. We will finish going over examples for the homework assignment tomorrow. Please email me with specific questions on problems or see me personally. If there is enough interest in a particular type of problem, I can make a podcast covering the material and go over it in class.

First Day of Class

Welcome to Mr. Brueckner's AP Chemistry class. I hope that we have a really good year together. You need to complete the following by Friday, August 20th, 2010.

1. Print a copy of the Classroom Policies and Procedures found on Mr. Brueckner's Chemistry page. The copy needs to be signed acknowledging that you and your parent(s) / guardian(s) are aware of class expectations and grading policies.
2. Print a copy of the Lab Safety Agreement, which can be found on Mr. Brueckner's homepage. The agreement must signed by you and your parents. Read over the safety contract and be prepared for a 20 question lab safety quiz on Friday, August 20th, 2010.

You also have a deadline for the first WebAssign assignment. Chapter 2 needs to be completed by Monday, August 23rd, 2010.

First Week, What to Expect

Your first assignment on WebAssign has been posted. You need to complete it by Monday, August 23rd, 2010. There will be no unit test over Chapter 2 in the book. You only need to complete the homework assignment for Chapter 2. There will be a quiz related to material in Chapter 2 that is not covered by the homework on WebAssign.

Welcome to AP Chemistry at Heritage High School

By now you have either received the email from me (Mr. Brueckner) or you have by chance found this site. Either way, welcome the the journey that will be known as AP Chemistry at Heritage High School. To reward you for finding the site, I will reward you extra credit if you perform the following:
E-mail me at cbrueckner@lps.k12.co.us and in the text, include your name (first and last), the best contact phone number for YOU (not your parents), and you must type in the e-mail the phrase "Yabba-dabba-doo." If you do not give me the phrase, NO EXTRA CREDIT! Please do not question why I require the phrase, just type the phrase. Please do this from an e-mail address that is yours (once again, not your parents) if possible.
Please go to my site on the school website (under Teacher Pages) or look back to this site periodically through the summer for information about the AP Chemistry class taught by me. Take care and have a good summer.