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Professor, can you please post the final key and also can you show us what the median, mean, and standard deviation were. Thank you, it was great taking your class.
Some of that info will be posted by Monday. MGG
DEAR PROFESSOR, WILL YOU BE POSTING THE KEY TO THE FIANL EXAM, AS WELL AS THE GRADE DISTRIBUTION ON VOH? IF SO, WHEN WILL THEY BE POSTED? SINCERELY, REEMA SINGH
Yes, They will be available this Monday. MGG
Dr. G, I heard that the calculation of specific rotation by use of the formula was not going to be necessary. Is this true?
Dear Fabiola, You do not need to memorize the formula if that is what you mean. However, you need to understand the formula and know how to use it if it is given in the test. MGG
Professor, what is the difference between aromatic, antiaromatic, and nonaromatic? Also, will you have extra office hours this week before the final? Thank you.
Dear Mark, Aromatic and antiaromatic systems have cyclic arrays of pi-orbitals and are fully conjugated. Aromatic systems have 4n+2 electrons (2,6,10, etc) and antiaromatic have 4n (4,8,12, etc). Non aromatic systems are those that are not fully conjugated because the cyclic array is interrupted by a saturated carbon or because the orbital involved do not ave a good overlap. I am sorry I will have no office hours this week. Please check with your TA's. MGG
Hi Professor. I just needed you confirm something. To figure out absolute configuration on a molecule with one chiral center, we look down the carbon bond to the substituent group of the lowest priority. In compounds with multiple chiral centers, we look down the carbon-carbon bond, right? I can't find any mention of this in the book that will say this directly.
see below
Hi Professor. I just needed you confirm something. To figure out absolute configuration on a molecule with one chiral center, we look down the carbon bond to the substituent group of the lowest priority. In compounds with multiple chiral centers, we look down the carbon-carbon bond, right? I can't find any mention of this in the book that will say this directly.
Absolute configuration is a property of a chiral center (not of a whole molecule) so it is assigned one by one using the same rules. You asign them by looking down the bond to the substituent group of the lowest priority. MGG
Hi Dr. G., I was wondering when our final was. Is it at 8:00am or 8:00pm on Wedneday? Different people have been telling me different times. Thanks a lot. Also, will the final be an hour and half, or two hours? Thanks alot.
Dear Ashwin, The final is at the time scheduled by URSA. It will be 2 h. Good luck, MGG
Professor, can you please explain a number 10.h. on the Chapter Problems. It asks us to determine whether two structures are enantiomers, diasteromers, structural isomers or identical molecules. The books says, 10h. are diastereomers, is this correct? If it is can you please try to explain it. Thank you for your time.
Dear Vid, Problem 10 compares (3Z)-1,3-pentadiene with (3E)-1.3-pentadiene. It is best to just consider them geometrical isomers (see the chart in p. 224). Best wishes, MGG.
Would you please post the keys for the midterm from before/
done...
Hi Professor. I was wondering if you could post the answers to the problem set you gave us on the Week 8 handout. Thanks for your time. Michelle
Dear Michelle, I think it's done. Best wishes, MGG
Prof Garibay, please post your past Finals and their keys if possible. That would help greatly. Thanks.
Should be there...
Will the keys for the midterms be posted online so we can use them to help study for the final?
Dear Jenny, I think it's done. Best wishes, MGG
Professor, I had a question on exercise 5.4. What does it mean when it says to estimate the energy difference? Also, on exercise 5.12, I understand that part a) has no center of chirality because there are carbon bonds on both sides. But, how does the Br in part b) account as a center of chirality? Doesn't it have a carbon on both sides? In 5.13 d)How do you set the priority? Some only count for one element and others have multiple bonds involved. Thank you Esther
Dear Esther, Problem 5.4 requires your understanding of the equilibrium equation, DeltaG=-RTLnK with K=A/B. Please review your 10B notes. In 5.12, a) is not chiral because it has an internal mirror plane. In part b), the bromine-bearing carbon and the chlorine-bearing carbon are the chiral centers, not the bromine. Set the priorities the same way you do it to asign (Z)- and (E)- isomers. Good look, MGG
hi professor, I was wondering if you would give us a periodic table on the final ( for atomic weight comparison)..especially for those of us in haines 39 because there is not one on the wall. Thank you!
Dear Sara, That is a good idea. Thanks for bringing that to my attention. Best wishes, MGG
Hi Professor, I'm confused about disubstituted cyclohexanes on pgs. 246-247. For cis-1,4-dimethylcyclohexane how do you know that one methyl group must be axial and the other must be equatorial and that in trans-1,4-dimethylcyclohexane either both are equatorial or axial,and in trans-1,3 dimethylcyclohexane either they are both equatorial or one is axial and the other is equatorial. I don't understand how the book arrives at these arrangements. Also, on which handout are those practice IR graphs you were going over in class today? Thanks for answering my questions.
Dear Annie, The author of the book arrived to those conclusions, and you can too, if you make molecular models of cis and trans 1,2- 1,3- and 1,4- disubstituted cycohexanes and then analyze them. Remarkably, all the stereochemcial relations can be deduced by anlyzing the models! Best wishes, MGG
Hi Professor, On your midterm, the nomenclature was much more difficult than the "Name It!" program and text book problems. I was wondering if you have some suggestions on where to get more practise problems so i can improve. Thank You! -T
Dear Teresa, The nomenclature problems in the exam are an extrapolation of the rules and examples in the text. The examples in my handaouts are a lot more difficult than those in the book but easier than those in the exam. I suggest consulting other textbooks for additional problem. best wishes, MGG
Hi Dr. G, I was reading Chapter 3 and on page 129 I cam across a diagram of an Amide. In this structure, the amide had two methyl groups attached to it, but on the previous page, an amide diagram showed two hydrogen atoms connected to the nitrogen, with no mention of there being a possibility for R groups. Can you please explain...thanks! Isaac
Dear Isaac, The functional group amide consists of a carbonyl flanked by an amine. Primary amides have two H's, secondary amides have one H and tertiary amides have no H at all. Best regards, MGG
Dear Professor, I'm confused about IR spectroscopy: Why do C-H bonds have a higher frequency than C-O bonds? Aren't they weaker and don't they have smaller dipole moment than C-O bonds? So shouldn't they be to the right of the C-O bonds in the IR graphs? Thanks.
Dear Eva, C-H bonds have higher frequency than C-O bonds because the difference in mass beteen C and H is much greater than the difference in mass between C and O. C-H bonds do have a smaller dipole than C-O bonds and that is why they are much smaller in intenisty (they are tiny little peaks). It is apleasure to answer good questions. Best regards, MGG
Hi Professor, I was wondering if you'd post an old final for us to practise with. I checked on the Winter 96 VOH for old finals, but they are not there. Thanks! T
Dear Teresa, Good suggestion, I'll check my files and look for that. MGG
Dr. MGG, I am from the other 10c section (sorry I am not using my own web page, but I find your handouts and exams quite helpful.) I was wondering if the practice midterms you have up would have a key? Thank You very much. Sorry, again, that I am taking up your time and am not an enrolled student in your class but I have worked out most of the problems and it would be nice if I could check them. will they be posted. Arta
Dear Arta, I do plan to post those keys, this weekend, Good luck on your class. MGG
Professor, On the syllabus the final is dated Monday March 25 (which is really the 23)from 8-9:30 pm. Ursa has the course final on Wednesday March 25 from 8-11 am. Could you please confirm the final date. Thanks, Tracy
Dear Tracy, The final will be at the time indicated in the schedule of lectures. Wednesday March 25, 8-9:30 pm. MGG
Professor, I'm looking at the schedule syallbaus and it appears that we are at least two lectures behind. Are we going to make up that day when you werent here? Also, how do we go about requesting regrades for the midterM? And also, can you please check VOH more often...I'm still waiting for some of my questions submitted last week to be answered. Thanks for your time! Eugene
Dear Eugene, We will cover Chapter 5 during the last week. I plan to lecture on NMR but will not include it in the final. I apologize for the delay in answering VOH questions. I will try to keep up. MGG
hey Professor, on the midterm question concerning aromaticity, we also needed to draw energy orbitals. however, i drew energy orbitals showing how where the electrons were located and what bonds they formed and was given no credit. the answer given in the midterm key were examples of "molecular orbital diagrams." I understand the difference between the two and know how to do both of them, but the question was ambigous in is wording. On our past homework ,adn even the practice midterm we did for our review session, the diagrams are referred to as "molecular orbital diagram/theory"...and the other as energy orbitals (pi, sig, etc)...but the midterm wording was "orbital energy.." THerefore, shouldn't the drawings be orbital energy diagrams instead of molecular orbitals? thank you, David
Dear David, There are no "energy orbitals". There are molecular orbitals (showing atomic orbitals with the correct phases and overlap) and then there are energy leves for orbitals (or, energy diagrams). Sorry about the language confusion. However, credit was given appropriately. MGG
hi professor, I was looking over the midterm key posted and it occured to me that there must be an error on the test. I was unsure of it while I was taking the test, but I asked my TA and he also confirmed it. The error is on the problem that asks us to draw five isomers for C5H8 and it also says that these are cycloalkanes. The answer you drew on the key are bicycloalkanes. The question for the test did not say that bicycloalkkanes, it specified only cycloalkanes. Because of this misprint, I was left stumped during the test. Many of my peers also noticed this error. Will there be a regrade, or throwout of this problem? thanks, David
Dear David, Althoughh there was an error on the test. Many of you had credit for knowing how to deal with the problem. Many people had the right answer and many people had cyclalkenes. There will be no regrading of that one. MGG
On the spread sheet for the post lab of the kinetics experiment, it talks about column F as the Constant, which is the same for all cells. To what constant are they refering to? Thank you
Dear Matthew, I will have to see that to be able to help (if this is an electrochemistry lab, could it be Farady's constant). MGG
Dear Professor, I was wondering when the final was going to be since on the syllabus the date of the final is March,25 (Monday 8-9:30pm) and on the schedule of classes it is listed as Wednesday, March 25 (8-11am). Thank You, Cindy Juarez
Dear Cindy, The final will be as listed in the Schedule of lectures. MGG
Hi Professor, I was just wondering if you can tell us the answers to the nomenclature part of the review sheets with the Bu and Ph substituents. Thanks
Dear Caroline, The problem with the Bu group: 4-Ethyl-2,5-dimethylnonane. The problem with the Ph: 4-Ethyl-2,3,7-trimethyl-6-phenyl-nonane. Good luck, MGG
Professor, Can you please rank these from higher to lower stability? hexane, hexene, hexyne, cyclohexane, cyclohexene and cyclohexadiene. Is haxane more or less stable than hexene? Also, is cyclohexane more or less stable than cyclohexene? Thank You
Dear Bobby, Your series contains different types of structures. You cannot compare those structures to one another. However, you can compare features of their structures. For instance, you can compare different types of C-C bons and C-H bonds. You can compare primary carbons to secondary carbons and so on. You could compare heats of formation and compare all those structures realative to the elements. To do that, I need to look up tables. Sorry about answering this late. Hope this helps. MGG
Professor Garcia Garibay, On your winter 97 midterm,I have two questions. On #6(a), i am kind of confused on the naming of it because i know it is trans but there is only one methyl on Carbon 2. So would it be trans-1,2(methyl cyclobutyl)-3-ethylpentane or would it be trans-1,2-(2-methyl cyclobutyl)-3-ethylpentane? On #8, on the second struture, is it nonaromatic or antiaromatic because if you count the lone prs on N, then it does not obey huckel's rule but if you ignore the lone pr, it is nonaromatic. Which one would you choose? Thank you!
Dear Sara, I am lookinh for the answer key. That will answer your questions. MGG
Hi Professor, I had one more question. On the sheet from the review session, Thermochemical diagrams part b, what is the answer? The question asks to predict the heats of combustion of hexane, 2-methylpentane, and 2,3-dimethylbutane. Thanks.
Hi, The more branched an alkene the more stable it is. MGG
Hi Professor,I was looking at the handout from the review session and I had a question. In one question you ask us to draw the structural isomers for C6H10 and C5H8. I see that both of these are alkynes and I was wondering, how do you draw structural isomers for alkynes? Also, can you please explain hyperconjugation again, and how you determined for the problem on the worksheet that Hc and Hh are the hydrogens in hyperconjugation in the double bond. And, I was looking at problem number 7 of your winter 96 final where you ask to rank cyclopentane, 1-ethylcyclopropane, and 1-methylcyclobutane with the more stable one first. Can you please briefly explain your reasoning why cyclopentane is most stable, then 1-methylcycloprane, then 1-ethylcyclobutane? Thank you
Dear Annie, To draw isomers alkenes, change the connectivity on either side of the triple bond. To match the fromula you can also draw cycloakenes. Hyperconjugation rquires that pi-orbitals are parallel to the sigma bond to which they are hyperconjugated. Problem 7 inthe W96 final relates to ring strain. Good luck, MGG
dr. mgg, can a compound be aromatic if it is two aromatic rings are connected by a chain of carbons. eg. cycliccmpd/\/\cycliccmpd, if the e-s present were in fact, lets say 14??
Dear John, The general answer is yes. If you have one or more 4n+2 electron cyclic pi-systems the compound is said aromatic. However, in the case that you describe, you would be referring to "two aromatic systems CONJUGATED with one another" (if there are double bonds between them) rather than a unique aromatic system. Best regards, MGG
Dr GG- I've gone a bit ahead in the reading and was wondering if a 1,4-cyclohexadiene could still take a chair conformation with the two parallel sp2 hybrids opposite to each other. Also, how does one go about dealing with chirality in octahedral species such as phosphoric derivatives? -Isaac
Dear Isaac, Molecules like 1,4-Cyclohexadiene have different conformational alternatives than cyclohexae itself. A chair-like conformation would cause torsional strain to the double bonds. If you analyze a model you can find that 1,3-cyclohexadiene should have a strong tendency to be plannar. The rules of chirality as the same for all coordination types. Compounds having a mirror image that is not superimposable with themselves are enantiomers. In the case of octahedral compounds we do not care as much as the number of different ligands as we do about the symmetry of the complex. We can take a closer look at that a bit later. Best regards, MGG
Dear Profeesor Garcia Garribay: Can you please post the awnswers to your practice midterm that you gave in class. Even though the midterm is over, I would like to have it for the final. Thankyou, Tawny Saleh
Dear Tawny, I will try to post all the answer keys in the next couple of days. Best regards, MGG
Dear Professor, I was wondering if you were going to post the answers to the homework problems for weeks 7 and 8. Also, are the answers to the old midterms going to be posted? Thank you, Minah
See previous answers
Professor, Today in class you said that we do not need to know functional groups for the midterm. Does this mean that we should not study chapter 3 at all for the midterm or are there going to be topics from chapter 3 on the test. Most of the chapter is on functional groups. Thanks.
Same answer as before
Hello Professor. You mentioned in class today (Wednesday) that Functional groups would not be on the midterm exam. Does this mean that Chapter 3 is no longer necessary? Otherwise could you please let us know exactly what chapters the midterm will cover? Thank you for your time.
Dear Amir, Everything up to todays class before functional groups. Best wishes, MGG
hi prof! can u please post the answers to the week 2/3 homework problems and also answers for the MIDTERM 97 that u posted. also, if i'm correct, functional groups will not be on the midterm...however, will dipole moments and polarity be covered? thanx
Dear Juoui, Functional groups will not be includede in the text. MGG
Will the key for midterm winter 97 be posted?
Hopefully
Hi again Professor, I was wondering if you could please post the answers to the winter 97 midterm as well? Thanks.
I'll try
Hi Proffessor Garcia. How are you doing? I was just wondering if you were going to put up the answers to last weeks and this weeks homework problems on VoH?
Dear Sara, Answer keys are being posted regularly. Bst wishes, MGG
Hello Dr. Garcia-Garibay, I was wondering if you could clarify what hyperconjugation means in a physical sense. Thank you Jose
Dear Jose, Hyperconjugation is a source of stabilization to double bonds. Was the model shown in lecture today clear? If not, if you have a chance, during office hours, we can analyze the model further. Let me know. I'll try to make it clearer. Best wishes, MGG
Professor, WOuld you post the key for the 97 midterm? How are we supposed to learn from and check our answers if we do not have the key? Please post this as soon as possible. Thank you esther
Dear Esther, One way you can learn from sample test without having the key is by working with other students, comparing answers, etc. You can alway check by analogy with similar problems answered in the book. I would be really impressed if you did that. However, the key would help. I will post it if I find it. Best wishes, MGG
Hello Professor, Thanks for posting your past midterms on VOH. But is there an answer key for the winter 97 midterm? Thanks
I'll Check, MGG
Hello Professor, You mentioned that you were going to give us extra problems instead of quizzes. Where do we get the extra problems that you talked about? Are they the problems on the handouts from lecture? Thanks, Catrina
Dear Catrina, They are the problems in the handouts. Good Luck, MGG
Hi Professor, I was wondering, are we responsible for functional groups eventhough we haven't covered them in lecture yet? If so, will we be responsible for naming them in complex molecules? Thank you for answering my questions.
Dear Annie, No functional groups for the mideterm. Good Luck, MGG
Hi Professor, I was re-reading chapter 2 and i noticed that there are certain polycyclic aromatic hydrocarbons like pyrene and naphthalene that were on the homework. Are we responsible for memorizing these structures? Also, should we know the structures of aniline, styrene, anisole,phenol,and toulene? Thanks a lot. -Sara
Dear Sara, Just memorize the tables indicated in the schedule of classes. Other names will be given with formulas in the text. Best wishes, MGG
Hi Professor, I was re-reading chapter 2 and i noticed that there are certain polycyclic aromatic hydrocarbons like pyrene and naphthalene that were on the homework. Are we responsible for memorizing these structures? Also, should we know the structures of aniline, styrene, anisole,phenol,and toulene? Thanks a lot. -Sara
Dear Sara, Just memorize the tables indicated in the schedule of classes. Other names will be given with formulas in the text. Best wishes, MGG
Hi Professor, I was re-reading chapter 2 and i noticed that there are certain polycyclic aromatic hydrocarbons like pyrene and naphthalene that were on the homework. Are we responsible for memorizing these structures? Also, should we know the structures of aniline, styrene, anisole,phenol,and toulene? Thanks a lot. -Sara
Dear Sara, Just memorize the tables indicated in the schedule of classes. Other names will be given with formulas in the text. Best wishes, MGG
Hello Profesor, I was wandering what will be covered on the review session on Weds Night (i.e. is it going to be question-answer session)? Thanks, Gabriel
Dear Gabriel, We will work on a problem set that I will hand out. We will use to the problem set as a starting point for all of you to ask questions. Good Luck, MGG
Hi professor, I was wondering, in problem 2.8 it mentions disubstituded and trisubstituded compounds and how stable they are. Can you explain what the di- and trisubstitutions mean in terms of double bonds as well as why they affect stability? Thanks.
Dear Bobby, Problem 2.8 refers to the number of groups other than hydrogen that are attached to the carbon atoms bearing the double bond. 1-Butene is said to be monosusbtituted, the 2-Butenes (both cis and trans) are said to be di-substituted. 2-Methyl-2-butene is said to be trisubstituted and 2,3-dimethtyl-2-butene is tetrasubstituted. Increasing the number of substituents attached to the double bond increases the stability of the alkene (i.e., it becomes much harder to rotate about the double bond). The reason for that is that substituents stabilize the double bond by hyperconjugation, which, as shown in Figure 2.10, and is based on orbital intercations. Hope this helps. Best regards, MGG
Professor, where is the previous midterm that you announced was going to be posted on VOH? I wented to the Chem10C lecture 2 VOH as I usually do but I failed to find the midterm. Is it posted somewhere else? thank you esther
Dear Esther, See my answers above. Good Luck, MGG
HI prof! have u been able to post a past exam on VOH yet? besides the practice exam we are going to take together during review session, can u please post another exam on?
Dear dave, Previous midterms should be posted today. Best wishes, MGG
Hi Professor, I was wondering if you can please post an old midterm on voh to help us study for the exam. Also, will we be getting the solutions for the problem set on the handout you handed today and the supplementary homework problems? Thank you for answering my questions.
Dear Annie, The two previous midterms will be posted today. I will also prepare a key for the problem set. Good Luck, MGG
Dear Professor Garcia Garribay: I have a question on Chapter #2 Exercise 2.15c. For this problem I though it was para ethyl toulene. The problem mannual says that it is meta ethyl toulene. Please expalin for me the reasoning on why it is meta and not para. Also, I am having some difficulty on distinguishing if the structure is entengen or zussamen. Also, are we going to be tested on material from "Braving the Elements". Thankyou, Tawny Saleh P.s. Can you please e-mail me at both MShirazi@AOL.com or Tsaleha@ucla.edu?
Dear Tawny, The correct answer for 2.15c is indeed para. The solution manual must have an error. I hope that the (E)- and (Z)- naming system became clear after the handout (which is also posted in voh with the title naming alkanes 3). As far as braving the elements, reading and understanding within the context of the lecture material will do the job. Good Luck, MGG
Hi prof! I was looking at the syallabus again and it occured to me that the final is posted as on monday 25, 8-9:30. This must be an error because monday is the 23rd. Also, i think if the final is on monday 23rd, this will conflict with people who are taking LS 1. I know there are alot (over 40) people who are enrolled in both LS 1 and Chem 10C...which would result in a final conflict time. please address this issue. thanx! john
Dear John, Thank you for letting me know about the error. I just made the correction in class today. The final will be Wednesday March 25 8-10:30 (8-11) in CS 50. Best regards, MGG
Hi Dr.Garibay. I was wondering up to what reading will the midterm cover. Does it include everything thruogh week 8 on the syllabus or what we cover in class up until the midterm? Thank You
Dear Steve, Everything up to Wednesday lecture. Good luck, MGG
Dr. Garcia Garibay- I was just wondering what topics would be covered on this friday's midterm. Will it cover subjects outlined on the syllabus even though we may not have covered it in class yet? Thanks.
Yes, the topics listed in the schedule of lectures and lecture material covered up to Wednesday. Best wishes, MGG
Dear Professor, On the HW problems 1.9 e, shouldn't the answer be 5-ethyl-4-isopropyl-3-methylnonane, rather than 3-methyl-4isopropyl-5-ethylnonane. I though that you said that IUPAC follows alphabetical order in its nomenclature. Thank You
Indeed, you are correct. MGG
Hi Prof! I was just wondering if you're going to put more emphasis on material covered during lecture than from the reading for the midterm? Thanks! And the models that your bring to class really help! Carolyn
Dear Carolyn, The midterm will cover mostly material like that presented in lectures but it will also include problems like those assigned in the book. Glad the models help. Best wishes, MGG
Hi Dr. Garibay, I was reading about benzene and arenes. Related to their cyclic structure, I had a question. In the previous chapter their was discussion about ring strainf on cyclic hydrocarbons. I was wondering if ring strain affected the energies of arenes too...there is no mention of it in the book. Also, I appreciated the solutions to the homework problems but I was wondering if you could make them in a larger font next time...it was very difficult to read. Thank you very much, Isaac
Dear Isaac, Arenes can also have strain if their geometries cause some atoms to have bond angles that are different from 120 degrees. There are many polycyclic aromatic compounds that are strained. There can also be steric strain when two bulky substituents "bump" against each other causing some bond angles (or bond distances) to deform. Thank you for your comment on the solution to the homework. We will post more readable documents. Best wishes, MGG
hi prof! i'm wondering if we are going to be able to use a notecard for our midterm next week...also can we use our atom models as reference during the test? thanks alot ..one more thing...will we make up that day that we missed? and the information...? geri
Dear Geri, Regarding notecards I will make anouncement in lecture. You can use your molecular models during the test. We should be able to make up Monday's class through the end of the quarter. I am planning to schedule a review session for Wed evening and I will make an anouncement on that this Monday. Best regards, MGG
Professor Garcia Garibay, Hi!I was reading the book and i noticed that there are a lot of topics that are not covered by homework..are we responsible for these topics? Additionally, some of the problems assigned in the supplementary exercises do not have an answer key. Could you post the answers to these problems and post the worksheet that was handed out on Wed lecture on VOH too?Thanks a lot!-Sara
Dear Sara, We will concentrate on assigned reading, recommended problems, lectures, and additional problems handed out. The last handout should already be posted and the answers to supplementary problems will be posted soon. Best wishes, MGG
Professor Garcia-Garibay, Hi, again. By the way, I really enjoyed the demonstrations in class today. I had a question concerning the same handout dealing with naming alkanes. On the back there are some additional problems. For number 1 are we supposed to just name these linear structures? Also, for number 2, how do we determine and indicate a tertiary carbon and a primary carbon in the two structures given and in any other structure that we may encounter in other problems? About the midterm, will it cover up to the material that we cover on Wednesday of that week? Also, in dealing with the handout given today about combustion, I had a couple of questions. To clarify, is it correct to state that the less the heat of combustion, the more stable the structure? My rationale behind this statement is that, for an alkane, it prefers to have a bond angle of 109 degrees. Cyclohexane is therefore more stable than cyclobutane with 90 degrees. Is this correct? Also, does this apply to alkenes and alkynes? Thank you Sincerely, Esther Hong
Hi Again, For number one, yes. For number two, identify as primary arbon atoms all the methyl groups (R-CH3 with R being any hydrocarbon chain, also known as an alkyl group). Secondary charbons are those with two H's: R-CH2-R. Tertiary carbons have only one hydrogen (R2CH-R), and quaternary carbons have no hydrogens (R4C). Best wishes, MGG
Professor Garcia-Garibay, Hola, yo tengo dos preguntas sobre quimica. That was just a little spanish that I wanted to use. Back to english :) On the handout concerning the rules and examples on how to name organic compounds of alkanes, I saw some things that I found confusing. The structure on the right in the middle ends in -undedace. What does this "un" stand for in this name? Also, on the last structure, the naming of the structure seems to be not alphabetical. It starts with Ethyl, then Dimethyl anf then, two Methyls. Why is the ethyl before dimethylpropyl? Isn't it supposed to be in alphabetical order? This is concerning something else, but I wanted a clarification on how we determine the hybridization of an element. Thank you very much. Sincerely, Esther Hong
Dear Esther, Good Spanish and good English... ahora hablemos algo de quimica (now lets speak some chemistry): Regarding the nomenclature handout, UNDECANE is the hydrocarbon chain with eleven carbons (check the back page of the handout). In the name that starts with 3-ethyl-... there is a mistake. Your observation is correct. It should be alphabetical with "Dimethyl... before ethyl before... etc. Regarding hybridization, there is a relation between the types of bonds (single, double, triple) and hybridization. Period two and three atoms bound with single bonds only are sp3, those that have one double bond are sp2 (>C::C<). Those that have a triple bond (alkynes, -C:::C-) or two double bonds (also known as cumulenes >C::C::C<) are sp hybridized. I hope this helps. Best regards, MGG,
Prof., is there going to be a review section for the midterm? If so, when and will it be organized or just a "question and answer" review? Thank you.
Yes, there will be a review session. I will hand out a problem set covering the skills and knowledge necessary for the exam. We will work through that and I will answer any qeustions that the class may have. I will anounce the time and place within the next one or two lectures. Best wishes, MGG
prof, hi. i'm reading the book right now....but the syallabus u gave us that has the matching book topics is kinda confusing. The topics do not correlate with the book. It would be really helpful if u could provide us with the page numbers that we should read in the book. thanks alot! eugene
Dear Eugene, I will take a look at that. Thanks for your suggestion. Best regards, MGG
professor, i'm confused about ur answer to the quiz question..will we be having 2 quizes? and when will they be? thanx e
Dear e, Rather than two graded quizzes we will be giving you additional problem sets for which we will be posting the keys (these will not be graded). The grades will be based on the midterm and the final. Best wishes, MGG
hi prof, i'm reading through the GST book..and it contains alot of information concerning the characteristics of atoms, compounds...etc..and history of chemistry in general. i'm wondering, do we need to memorize these for the midterm? also, i looked at past VOH files, and u don't have any midterms posted...will u be able to provide us with a past copy? or a study guide? thanx alot! banes
Dear Banes, The material in the GST textbook is not meant to be memorized. One or two questions will be related to GST but will be closly related to the material covered in class and in Fox and Whitesell. I will look into posting past midterms. Best wishes, MGG
Professor, In the solutions that you posted problem 1.9 part e has the answer as 3-methyl 4-isopropyl 5-ethyl, why would it be written in this fashion instead of alphabetically, do the #'s play some role in this? Thanks.
The correct name by IUPAC standards is 5-Ethyl-4-isopropyl-3-methylnonane; alphabetical ordering rather than numbering. It seems that this is an error in the solution manual (I have an older version and perhaps it has been corrected). Best wishes. Dr. Garcia-Garibay
Dr. Garcia-Garabay: I was wondering if you could tell me when the two quizzes will be, and what they will cover? Sandra
Dear sandra, Rather than two grades quizzes, we will give you varios additional probems sets for which we will post answer keys. The probem sets will be good samples of the type of material to be covered in the exams. Good luck, Dr. Garcia-Garibay
What is wrong with our book? There are no answers to sample or review problems, where are we supposed to find them? The solution manual is not yet available in the bookstore.
I just found out about the bookstore problem. I will have answers to assigned problems posted. MGG
Professor, Due to the fact that the bookstore is out of solutions manuals and that the answers are not in the back of the book, when will you be posting the answers to the assigned problems? Thanks.
Thanks for letting me know about the lack of solutions manual in the bookstore. I will try to have the answers posted early in the week. MGG