yes or no on alkenes??

[tootsies!]

i was wondering if any of you guys know if we have to study elimination and substitution reactions for alkenes...or if we have to even study any of the reactions involving alkenes...

the amcas/mcat student manual keeps saying "no alkenes" but i'm not sure because the reactions seem so important and EK and TPR both reviewed them.

does anyone know if we have to stress over these stupid alkenes??

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[inside_edition]

i was wondering if any of you guys know if we have to study elimination and substitution reactions for alkenes...or if we have to even study any of the reactions involving alkenes...

the amcas/mcat student manual keeps saying "no alkenes" but i'm not sure because the reactions seem so important and EK and TPR both reviewed them.

does anyone know if we have to stress over these stupid alkenes??

if it's that much of a problem for you, then just understand the concepts. By the time test day comes, you'll most likely have forgotten them. So then you can simply memorize it really fast. that's my gameplan for some of these odd topics (in sound for example, i keep on forgetting the equations. same with freq and period for hooks law and Simple Harmonic Motion.)

also does anyone know if we have to know angular momentum, angular velocity, angular acceleration, etc? I wouldn't be surprised if these concepts appear in an actual passage with the equations and explanations given (as opposed to having memorized and understood without reading the passage).

And what about pulleys? i could never get this concept right because I always used intuition when solving mechanics problems.

 

[rcd]

And what about pulleys? i could never get this concept right because I always used intuition when solving mechanics problems.

I don't have an intuitive understanding of pulleys either. I just have the w = f cos theta d memorized. w is constant, so if a pulley doubles d, it halfs f... I think it would come easier with a better understanding of energy (which our textbooks define in terms of w... leading back to the f*d equation).

 

[inside_edition]

I don't have an intuitive understanding of pulleys either. I just have the w = f cos theta d memorized. w is constant, so if a pulley doubles d, it halfs f... I think it would come easier with a better understanding of energy (which our textbooks define in terms of w... leading back to the f*d equation).

in pulleys i know that work=F(subscript-parallel) times d is constant. But i can't seem to analyze the set up in the picture. i do, however, understand that pulleys use the concept of mechanical leverage and work.

i think i should draw a free body diagram for every "wheel" on the pulley until i can figure it out intuitively.

 

[dovebar]

Ahhhhhh....another 40 more days of this.

 

[Dr Durden]

Alkenes are just covered in the review materials because they are so fundamental and are likely one of the first set of reactions encountered in any organic chemistry class. The test prep companies are just covering all their bases and honesty, don't update their material that much from year to year.

Focus instead on more complex functional groups, ESPECIALLY those with more biological significance. Something like reducing a double bond over a metal catalyst or cleaving it with hot acid won't show up. On the other hand, amides and esters will likely (and to let you in on a little secret they were) huge on the MCAT.

That being said, know your mechanisms and not just reactants and products. Be able to say where any given atom will end up on the finished compound(s), and conversely, where it would have been on a reactant. Be able to predict chirality of products. Most any premed can make flashcards and memorize reactions, but these more complex concepts will separate the men from the boys on test day.

Best of luck.

 

[tootsies!]

thanks for the responses...maybe i'll gloss over them. i still kinda remember them from soph year...but i won't be stressing over it...

...i'll stress over physics instead!

 

[dufflebag]

Alkenes is not tested on MCATs per AMCASS. Although review Alcohols, SN1 SN2 reactions. I did not see too many complicated alcohol reactions. Understand and predict the reaction outcomes, you should be just fine.
Best

i was wondering if any of you guys know if we have to study elimination and substitution reactions for alkenes...or if we have to even study any of the reactions involving alkenes...

the amcas/mcat student manual keeps saying "no alkenes" but i'm not sure because the reactions seem so important and EK and TPR both reviewed them.

does anyone know if we have to stress over these stupid alkenes??

 

[abcxyz0123]

so wait, does this mean I can ignore section 2-6 to 2-12 in examkrackers organic chemistry? That section is all alkenes, but it includes information about electron donating and withdrawing groups. Is everyone just ignoring this section, or memorizing/learning certain parts of it?

 

[NontradICUdoc]

Pullys and ramps are just machines. Keep in mind that all they do is reduce the force required to do the same amount of work.

In a pully system, first thing, draw the diagram and label where the forces are. Remember that work is Force X Displacement. In a pully you have 2 forces working, Gravity pulling downward and Tension of the rope(s) pulling upward. You need to find the NET force.

If you set the forces upward=forces downward, then you can get the force in each direction. If the system is pulling the weight upward, then you know that Tension > Gravity. If the block is moving downward then Gravity > Tension. If the block is not moving then Tension = Gravity. If you find the net force, multiple this by displacement and you have work done by the pully.

 

[NontradICUdoc]

so wait, does this mean I can ignore section 2-6 to 2-12 in examkrackers organic chemistry? That section is all alkenes, but it includes information about electron donating and withdrawing groups. Is everyone just ignoring this section, or memorizing/learning certain parts of it?

Do not Ignore anything. There have been many questions on SN1/SN2/E1/E2 reactions and plenty of them. Understand it. Know the differences between each and when is each favored. For example, you should know that if you have a bulky side group which substitution reaction is favored. Or if you have a weak base will the reaction proceed through SN2/SN1 or E1.

Electron donating and election withdrawing groups are important in determining acidity and questions on why the primary hydrogen is more acidic than the secondary.

Do not skip over anything for the MCAT. Pretend that there will be at least 2 questions for each concept.