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lan418

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Posts posted by lan418

  1. thanks for all the replies and concerns.

     

    I just recently got the test Key back and i banged my head on the table. I could of easily gotten a letter grade up if it werent for me making these stupid mistakes. For example, an E2 reaction, how its suppose to knock off Br and form an alkene with a strong base and tert-carbon group(so SN2 doesnt occur), I LEFT BR ON IN THE FINAL ANSWER!!!!! i was penalized and along with some other mistakes like that.

     

    I understand the material well but, with all my past chemistry experiences, i always do stupid mistakes and its painful to see those points go away after i review my test. Why do i always make such stupid mistakes, i didnt even feel rushed and i prepared for the exam.

     

    BUt aside from that, thanks for the good advices in this thread, i will take them into consideration.

     

     

    ...

     

     

    STUPID MISTAKES ARHGHAHHARHAGHARHGAHRHGAHRHAGHARHGH

  2. i thought about going into study groups, in fact the teacher strongly recommended it. But for me personally, for the past few months i have been teaching myself and going solo because i feel if i study in groups not much will get done and it feels as if im "convinced" to be prepared just becasue we talk about some things and there is no true understanding.

     

     

    It was a good suggustion for the prof. to grade my practice exams. He did post them on the internet and i work on them and try to understand why i got it wrong while practicing those problems.

     

    sigh

  3. Im in sophmore organic chemistry in college but i been feeling kind of depressed lately. I put in my fair amount of time studying the material and i never usually fall behind or procrastinate. But on the last test i did really bad. I really thought i understood the material to expect B or higher. But the professor's test was hard and the average score was a 66 out of the whole class.

     

    But i still dont know why i did so much for my time spent for preparation. HOw do/did you guys become good at organic and what are some tips you can offer? Also, it would be appreciated if you can provide some links that is very thorough for review and test concepts to make sure you have mastered them. Im pretty sure some people on this board had earn at least A or Bs in organic chem.

     

    Thanks for your time.

  4. O

    ll

    / \

    l l

    \_ //

     

    O

    ll

    / \

    ll l

    \ __ /

     

     

    Ok, this is the hexane molecule with the C=O bond on the top. In the first one, there is a double bond near the lower right and a double bond in the second molecule at the middle left. I'm wondering, as far as isomerism is concerned, is this a cis-trans isomer or a structural isomer and why. On my test i put structural, so i dont know if i'm right.

     

    Thanks in advance.

  5. ...in another context. I'm going to be making a discussion about how organic chemistry is not used as much in the medical field. Dont take me too seriously, this is just for a fun debate. I understand a few concepts of basic organic chemistry may be crucial, but anything beyond that is not necessary. This topic is solely on the subject itself, NOT on how med schools require and take into consideration how well students do in organic chemistry.

     

    I believe that the understanding more complex reactions taught in an organic chemistry course isnt applicable in the field of medicine. I find it more pratical in other fields, such as industrial chemistry. No doubt that they have to maximize profits with efficiency costs of trying to produce a reaction for a final product.

     

    But in the doctor's office, how often will the physician even consider a remotely relevant organic reaction for a prognosis or a diagnosis? Perhaps particular prescriptions may contain certain elements of organic compounds in the medicine but how often does the doctor consider it in an organic context rather than from experience and practice? I dont know how many of you have actually asked your doctors a question similar to this but what would a doctor say if you just ask him/her about a simple organic reaction for your homework? I believe most doctors wouldn't remember much. So in this little fun debate, what else can i mention about the issues that combine organic chemistry to the practice of medicine( to physicians)?

     

     

    Don't get me wrong, i love organic chemistry.

  6. I've been working on these problems for some time. However, i havent been able to rationalize the answer for the following problems.

     

    1. A 95.0 mL sample of He(g) is collected over water at 765 Torr and 56 degrees C. If, at these conditions, the "dry" V of this He(g) sample is 79.6 mL, the VP of water at 56 degrees C is closest to

     

    1. 94.5 torr

    2. 46.9 torr

    3. 79.5 torr

    4. 153.3 torr

    5. 123. 8 torr

     

    2. If water is saturated with a mixture of N2 (g) and a second gas at STP to give a solution which freezes at -0.00184 degrees X, and x(greek letter symbol chi) = 0.45 for N2 (g) above the water, the Henry's constant for the second gas is closest to

     

    1. 9.6 x 10 E-4 mol/L atm

    2. 2.2 x 10 e-3 mol/L atm

    3. 5.5 x 10E-4 mol/L atm

    4. 2.6 x 10 E -3 mol/L atm

    5. 1.7 X10 e-3 mol/L atm

     

    3. If a sample of an ideal gas in a closed flask exerts a P(pressure) of 560 torr at 125 degrees X and a P of 960 torr at 250 degrees X and T in degrees X varies linearly as a function of Delta P, absolute zero in degrees X is closest to

     

    1. -125 degrees X

    2. -25 degrees X

    3. -75 degrees X

    4. -100 degrees X

    5. 50 degrees X

  7. I understand what you're saying but why go through all those rigorous courses of chem when you're only going to use a small percent of knowledge from chemistry? Im a microbio major at University of Florida. Our "critical" tracking courses consists of chem 1, 2, organic 1, organic 2 and biochem

  8. One scenario i commonly see at my university(possibly goes on in other universities also):

     

    Person 1: So what are you studying?

     

    Person 2: I want to go medical.

     

    Person 1: oh, what classes are you taking?

     

    Person 2: ::says various courses:: And im taking chem.

     

    Person 1: oh, how do you like it

     

    Person 2: i HATE chem

     

    It is possible to go pursue a medical career with a resentment for chemistry? Chemistry is so important to medicine and it seems most of the undergrads want to go medical because of financial stability for the job. Do you think it's possible for them to still carry on with medicine with no desire for chemistry and just "tough" it out? I mean, a person cant like medicine without having a fond interest of chem, right?

  9. For the net ionic equation, you drop the Na+ because it is soluble(refer to your solubility rules in your textbook).

     

    You are left with the H+, CLO- and S2O3 2- ions. You can take it from there.

  10. Reaction:

     

    Mg2+ + OH- ----> Mg(OH)2

     

    Ca2+ + OH - ----> Ca(OH)2

     

    Molarity values can be found in my first post.

     

    Brokenbin, is there a specific reason why Calcium doesnt dissolve as easily as Magnesium? (i.e. different atomic weights, conformation)

  11. The experiment is a basic kind of precipitation reaction, you have 2 solutions in two bottles and you add to drops of each solution onto a sheet of transparency and see if precipitate forms. Well, one particular reaction that has me wondering was the .1M NaOH. First we mixed it with 2 strong acids and of course no reaction. 2 transition metals gave 2 precipitate. BUT, in group II the alkaline metals, we mixed .5 M Mg(NO3)2 with .1 M NaOH and no reaction occurred. However, when we mixed the same NaOH of same molarity with .1 M Ca(NO3)2 one guy in my group deciding that it was a precipitate present. Does Calcium Hydroxide produce a precipitate? Does Mg(NO3)2 form a precipitate? I found it funny how one element from Group II form a precipitate(the one with calcium) but the reaction with Mg didnt. Maybe we did something wrong because i thought the same elements from the same group exhibit the same manner. then my lab partner said that the reason was because Calcium was a heavier metal and for this reason there was a precipitate for the Calcuim reaction. Is that right?

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