sn2s

Some Tips On Organic Chemistry
  1. When you’re looking at two compounds and wondering how they may react, pay attention to the carbons - if they are bonded to a halogen or something more electronegative than them, then they have a partial positive charge and they’re going to want anything that will give them more electrons (a.k.a. a nucleophillic attack). If they’re bonded to hydrogen, they have a partial negative charge and they become your nucleophile, which will want to give those electrons to something that’s lacking them. Once you get these basics down, mechanisms become much easier to memorize because you can see the logic in them and sometimes predict them.

  2. Get the basic mechanisms ingrained in your brain. Think of SN1, SN2, E1 and E2 as your new multiplication table. Make flashcards about them and take them to class. Or put them at the back or front of your notebook. Just have them handy at all times.

  3. Draw the final steps in 3D. ALWAYS. You can draw the mechanisms and the first steps in 2D because it will make it easier to understand, but never forget that you’re working with a 3D structure that can flipped (and attacked by nucleophiles) every which way. Also, if you don’t know the basic perspectives used in orgo (Fischer, Newmans, sawhorse, wedge-dash) please take half an hour to learn them. Mainly wedge-dash and Fischer, but Newman is very useful when deciding which position you should put your atoms in if you’re dealing with sin and anti.

  4. Colors. If you’re one of those people who ONLY writes in black pen, awesome, keep using it for WRITING. For reactions though, you’re going to want options. you’ll need to differentiate between:

    • The molecules (same color for atoms and bonds, unless you want to finish your notes on your deathbed).
    • Your three types of arrows: electron flow, actual steps in the reaction (think intermediates) and steps you may take to make it clearer for you but that happen at the same time.
    • Formal charges
    • The electrons that stay with its original atom and the ones that are given/shared, if you’re like me and you like your mechanisms to be spelled out.
    • This is not an excuse to go nuts with the coloring, 3 colors are enough. Personally, I use purple for molecules, electrons and reaction arrows, black for electron flow arrows and charges and light blue for clarification step arrows. Also optional but to denote a homolytic fission I usually write a blue line perpendicular to the bond. Similarly, if two atoms share one electron each, instead of just one them donating both electrons, I link said electrons with blue.
    • Remember to be consistent, otherwise you’ll end up like me, looking at your notes from the beginning of the semester and wondering if that dash is a bond or a -1 formal charge (to avoid this, preferably circle formal charges. Lol I never do this but I should).
  5. Flashcards are so helpful! Write the reactants on one side and the mecanism and products on the other. Test yourself until you are one with the electrons.

  6. If it’s a concerted mechanism, number the arrows. You’ll thank yourself a month from now.

  7. Khanacademy. Khanacademy will save your butt when it comes to mechanisms. Chemwiki is likely to have anything that Khanacademy doesn’t. If it isn’t in either of those, Google images just became your new best friend. Books also tend to explain those nicely but I personally find them to be poorly structured and they usually include much more info than what you’ll actually be requiered to know. If you have the time to read two pages on a reaction though, by all means go for it.

  8. Study in advance. Good luck studying for your final two days before if you don’t understand the mechanisms and you don’t have your material organized. Seriously, don’t do it. A week before the exam you could make those flashcards mentioned above. They’re a great way to review but it will be impossible if you are learning these things from scratch.

  9. Get your hands on past tests. This goes for any subject but especially for orgo. Try to get a past test or at least ask an upper-classman who’s taken orgo with that professor. Does his/her tests focus on mechanisms? Retrosynthesis? Or does he/she give you the reactants and ask what the product is or what environment they should be in to obtain x? Ideally, you should be able to answer any of these if you know the material. However, if they focus on retrosynthesis, it may be a little tricky, so make sure to cater your study techniques to that.

  10. You should also check out @colllegeruled’s Surviving Organic Chemistry, it’s super helpful and it has lots of resources (seriously, you introduced me to Khanacademy, I OWE YOU MY LIFE).

So, this is what I can offer so far. I hope it shines at least a faint light into the dark path that is organic chemistry.

Other masterposts

Molecule of the Day - Dimethyl sulfoxide (DMSO)

Dimethyl sulfoxide (C2H6OS), also known as DMSO, is a colourless liquid that is commonly used as a reactant and solvent in laboratories and in the chemical industry.

It is classified as a polar aprotic solvent, and is capable of dissolving a range of both polar and non-polar compounds, and even ionic substances as well. Being an aprotic solvent, it cannot form hydrogen bonds with and stabilise nucleophiles, causing their nucleophilicity to be enhanced. As a result, SN2 reactions are preferred in such media over SN1 reactions and elimination reactions. (The photo below shows acetone molecules instead of DMSO, but the logic still applies)

DMSO is also used as a reactant in some reactions, such as Swern oxidation, in which alcohols are oxidised to aldehydes or ketones. However, while this has been an important synthetic technique in the past, its use is now gradually declining due to the production of toxic by-products such as carbon monoxide and dimethyl sulfide.

An interesting property of DMSO is that people have noticed a garlic-like taste in the mouth upon exposure to it!

The curious case of Gloria Ramirez, in which a pungent, garlic-like smell from her body after defibrillation was administered caused 23 hospital staff to collapse, has been attributed by some to her use of DMSO as an alternative remedy for pain. It is postulated that the DMSO was oxidised to dimethyl sulfate, which is highly toxic, upon administration of the electric shocks from the defibrillator, and this resulted in the mass poisoning of nurses and doctors.

Industrially, dimethyl sulfoxide is produced from the oxidation of dimethyl sulfide with oxygen. 

Requested by anonymous

OCHEM ONE MATERIAL: This is a super helpful chart to thinking about SN1 and SN2 reactions! 


The TOP ROW represents SN1 reactions. In an SN1 reaction, the leaving group (grey cat) leaves FIRST. The nucleophile (orange cat) then “attacks” the bed (carbocation) once it is empty. 

The BOTTOM ROW represents SN2 reactions. SN2 reactions are CONCERTED. This means it happens in one single step! The leaving group (grey cat) is kicked out of bed by the nucleophilic ATTACK (evil orange kitty). 


Hope this helps!

anonymous asked:

Todomomo/Kamijirou Double Date??

Note: This is a ~8000 word one-shot for Kamijirou and Todomomo, has a tiny mention of Izuocha (because my friend @c-jay321 loves them) as well. I hope you enjoy! The formatting also prob looks way better on comp.

This is entirely comedic and lots of fluff; Also a crap load of Kaminari and Todoroki bonding LOL 

In which Todoroki gets help from Kaminari

Keep reading

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Another MC from that princess game. If you play a MC from the pseudo-Eastern European kingdom, your background is that you are a recent widow who had married into a wealthy family, and is now looking for new ambitions.

Well, none of the kingdoms give the vibe of realistically having dark-skinned pocs as royalty (or as citizens), but I crowbar them in anyways if I can. And what better background than this one? A literal “Black Widow” for ya. Personality-wise, she’s rather conservative, calculating, and unexpectedly soft-hearted. Also, in this kingdom, the colour “red” represents mourning so I dawned her in it.

SN: She’s totally inspired by “Fancy” by Reba Mcentire. love that song.

SN2: I was trying to create a kokoshnik (a type of headdress)…hmph.

Molecule of the Day: Diethyl ether

Diethyl ether (C4H10O), also known as ethoxyethane, is a colourless, volatile liquid with a sweet, pungent smell at room temperature and pressure.

It is a commonly used polar aprotic organic solvent used in laboratories, and has low solubility in water. Therefore, it can be used in liquid-liquid solute extractions in conjunction with water.

Diethyl ether was also historically used as an anaesthetic - it was first used as such in the 19th century, and gradually replaced chloroform as an anaesthetic due to its lower toxicity. However, in recent years, its use has been largely supplanted due to its flammability and side effects such as vomiting and nausea.

Diethyl ether can be produced by the acid-catalysed condensation reaction of two ethanol molecules, which is how it is produced industrially as a by-product of acid-catalysed hydration of ethylene to produce ethanol:

Alternatively, it can be synthesised using the Williamson ether synthesis, in which an ethoxide salt is reacted with an ethyl halide to produce diethyl ether via an SN2 reaction:

While diethyl ether has a low toxicity, it has a tendency to react with oxygen in the air to produce highly shock- and heat-sensitive explosive peroxides, which is why old bottles of diethyl ether should be disposed of carefully as they may detonate.

The day has come and you’re finally forced to take that one class you avoided for many years - organic chemistry. Like most people, studying for chemistry is not particularly favored and can be tricky to know exactly what to study. It takes a lot more effort and time management for students; in which, the outcome is not always what they expected. Though, as a chemistry major and someone who got a reality check when going through the first semester of organic I want to give some personal tips on how/what to study!


1. Read the chapters assigned before lecture!
This is something that many students forget about or don’t feel like doing. (Haha, me) However, trust me it is the best thing you can do in organic because there will be days that you have NO IDEA what the teacher is talking about. Though, one day I decided to read the chapter with corresponding mini-notes in my notebook before the lecture and man did it help. This can be done the day before or even an hour before lecture (I prefer before lecture so it’s fresh in my mind) and it helped me know what questions to ask!

2. Ask questions or answer questions!
Yes, if you’re like me and get anxious to raise your hand this will be difficult to accomplish but once you break out of that comfort zone… it’ll be beneficial. Also, don’t be embarrassed if your answer is wrong! It helps to know why you didn’t get it right when the teacher goes on to explain the correct answer. This will help you change your thought process about the problems when you especially get into synthesis reactions and elimination reactions.

3. Revise notes after lecture!
After the lecture, if I didn’t have another class right after, I would take a colored pen and write side notes to revise them. Basically, this helped me make personal connections with the material. Note: can vary between each student so do whatever you’re comfortable with! 

4. DO PRACTICE PROBLEMS!!!!
No seriously.. Do every problem you can so the material and concepts can be drilled in your brain! When you get to alcohol synthesis, this is definitely important because those reactions can’t just be memorized. You’ll have to know the products formed and what solvent you need to use in order for the reaction to actually work.

5. Make flashcards!
I made them for the important things to know in my notes. By doing this, I could focus on the material that was the trickiest for me. Also, concept maps work for organic because it gives you a good layout of the chapter! 

6. Put some color in those notes!
This can help you navigate through your notes better and know how the reactions work. So, if you’re given an example of an SN2 reaction put the reactants in black pen, the solvent in red pen and the main products in blue pen. This can help know which compound is the electrophile and which one is the nucleophile. (I wrote little side notes on why they are each one for when I looked back at it) 

7. Buy Organic Chemistry as a Second Language by David Klein.
Or any other secondary textbook that gives extra help. The one I mentioned is particularly excellent because it’s in the format of a workbook and is divided by both semesters (I and II). The author has readings of each chapter and then works through problems with you to better your understanding of the concepts. (There’s more problems at the end of each section if needed with an answer key.) 

8. Go to the professor’s office hours!
Very straight forward tip… They like when you show interest in excelling in their class!


So there’s my take on organic and I hope everyone who is taking the class finds these tips helpful. Don’t be afraid to add more to this post with anything that helped you personally. Good luck!

2

Water Genasi

Water genasi are unusually patient and calm for genasi. Preferring to live alone, most are used to solving problems on their own and not afraid to take a lot of time doing so. They present a tranquil, somber demeanor despite whatever emotions flow underneath. They are skilled at observing life unseen, typically fading into the background, and shunning any interaction unless necessary. Other races have contempt for them, but see their ambivalence towards worldly events somewhat off-putting.

SN: Most of time, I fool around in photoshop until I’m lucky. This time, I got lucky with my water genasi.

SN2: Water was always my favourite element as a kid. 

anonymous asked:

I’m struggling so much with chem. I understand the concepts, but I have hard time with the quizzes snd midterms. Do you have any advice??

If you know the material and still struggle on exams, that’s because you don’t know how to apply the material in an exam setting. You follow along in the textbook but flounder when it comes to remembering the steps for, say, SN2 substitution. The only thing that will help in your situation is just doing as many practice exams as possible. 

In preparation for quizzes, you can’t just do the homework and expect to be good at it. Doing all, or almost all, of the problems in the back of the textbook is a must, and don’t do it all in one day. Space it out so that you’re doing some every day and keeping everything fresh. Also, if your textbook has problems that they work through in the chapters, writing those out on your own is so helpful and critical to your success. I know it’s busy work, but it’s the only thing that actually helps.

2

Familiar Spirits|

Not akin to Paganism’s definition of “familiars,” familiar spirits also refer to entities in Christian mythology who latch unto those wading in the comfort of grief for too long, in the “familiarity” of complacency. They seek to keep their host in the numb state they desire forever, steadily supporting the soul’s feeble existence while drawing life from it simultaneously. They are not necessarily ill-intended or cruel, yet are fatal nevertheless.

Upper: Avian spirit for those who propel themselves in life’s fast paces.

Lower: Feline spirit for those who bury into the layers of themselves.


(SN1: Humanized versions of the bird and cat FS side characters in a series of short stories I wrote.)

(SN2: Edited versions of @kurasoberina‘s HD Primer skin. totes superb, but I decreased the sheen/altered the dark bases so the details on darker skins show better for me.)

2

Bralani & Firre pt. 2


SN: The moment I saw that dress I knew….I knew its purpose.
SN2: I totally was inspired by Mongolian and Balinese bridal/dancer fashions. Not enough CC made for them =/
SN3: I’m woman enough to admit to watching the “Your Love” by Nicki Minaj music video while editing. 

mmmm, not the most culturally appropriate inspiration-wise, but even crazier there’s a song by her I like.

2

Pooja.

Very much inspired by old Bollywood films, where the women wore very “strong” makeup colours (especially in the historical pieces) and those classic, vibrant Indian paintings. 


SN: omg I’ve watched so many Hindi music videos my dreams are in garbled “Hindi-esque” speech lol.

SN2: and btw, she’s supposed to be wearing an anarkali, but ya know, cc and veil transperancy probs :x

3

My first gnome. In DnD I imagined gnomes to be to elves what halflings are to humans, fun-sized versions of them. DnD gnomes have lacked a lot of creative direction to the point I never know how to play one (eg. started as “big nosed, tan, and small” to now “diminutive human/elf w/ crazy hair colours). That said, I still want to try one out, and since IWD allows for full party creation, here’s my manip’d idea of a Rock gnome.

She’s a Neutral Good cleric of Baravar/illusionist mage. She’s a traveling companion of the Moon elf I posted yesterday(?). Long ago she chose to take a vow of silence unless casting spells; many have wondered why she’s done though. It’s speculated she was cursed with a truth spell long ago, and rather displease her god, she decided to not speak again….
Or, it could be she’s just not much a conversationalist. 

SN: I used a very edited base sim of morganaplays. Worked perfectly.

SN2: Just noticed super fuzziness. screw tumblr. click “HQ” images :)