Thermodynamics Question

Below are the three questions that you need to answer for tomorrow, Thursday, December 1st, 2011. This will be graded at the beginning of class on the due date.

Organic Chemistry Independent Study

As I have promised, you will be given the opportunity to complete an independent unit of study over the Thankgiving holiday break. This unit of study is completely voluntary, but it is something that will help you on the AP exam next may. I have mapped out below where all of the resources can be found can be found and what the procedure will be for finishing the material.

The independent study will cover 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 possibly 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 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 27th, 2011. 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 Fiday, November 18th, 2011. 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 Friday, November 18th, 2011. 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 Saturday, November 19th, 2011. 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 Sunday, November 20th, 2011, 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 27th, 2011.

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.

If you would like to look at a cool software, you may want to download a molecular modeling software called Jmol. Use the link for the download. It is free-ware that works surprisingly well. On the Events Calendar under the date Monday, November 21st, I have a VODCast showing how to use the software. If you download the software and use it to make a molecule, print a picture of the molecule, and correctly name the molecule, I will award you 10 points extra-credit towards your homework grade. The molecule must contain atleast four carbon atoms, atleast one double bond (or triple bond) and one functional group or halogen atom. If you have a hard time loading the software to your computer, just by-pass the software and draw me a picture of a molecule on paper, but it must be colored. A hand drawn picture will be worth 5 points 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 or text me if you need any assistance.

Take Home Quiz and WebAssign

Below is the take home quiz that you were promised for the weekend. Please complete the problem and have it ready to turn in on Monday, November 14th, 2011. I have also placed a WebAssign assignment for Chapter 10 that will be due next Friday, November 18th, 2011. Please remember to keep watching all of the review videos from the class calendar.

Chapters 8, 9, and 24 Exam 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. The multiple choice test will be given on Wednesday, November 9th, 2011 and the short answer will be given on Thursday, November 10th, 2011.

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.
    
    

Hybridization Recap

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. Associated with the tetrahedral parent geometry.



• 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. Associated with the trigonal planar parent geometry.



• 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. Associated with the linear parent geometry.

VSEPR Lab

You were given the VSEPR lab yesterday in class. The lab will be due next Friday, November 11th, 2011. 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.