The 4 Major Classes of Reactions in Org 1

by James

in Alkenes, Chemical Bonds, Organic Chemistry 1, Organic Reactions

Quiz time. Look at these reactions. Ask yourself this question for each: what bonds are broken, and what bonds are formed.

Don’t worry if you don’t understand the reactions. That comes later.  You don’t need to understand the reactions to be able to answer this question.

If you can do this successfully you are off to a good start. At least 80% of the reactions you will learn in Org 1 fall into one of these 4 categories. The sooner you can get into the habit of recognizing bond formation and breakage the better off you will be.

More about each of these patterns later.

Next Post In The Series: Introduction To Acid Base Reactions

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{ 9 comments… read them below or add one }

marcus

It’s kinda strange in your first case that you show a covalent bond forming between sulfur and sodium. It’s also strange that you show Na-OH instead of NaOH- same goes for the sodium ethoxide and NaCN.

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james

You’re right- I wanted to make it clearer for people to be able to see which bonds are forming and breaking, even if normally “ionic” bonds are drawn as covalent bonds. This is something you’ll see quite a bit of in textbooks, by the way – ionic bonds are commonly drawn as covalent, just to avoid drawing in the partial charges. You’re just supposed to “know” by later chapters that these bonds are ionic.

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mevans

I actually like the way you drew the first reaction, James, because the reaction is balanced. As a student, missing counterions in multi-step mechanisms used to drive me crazy (and still do)…

Dig the new site design!

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james

Missing counterions drove/drive me nuts too. I am glad I’m not the only person who feels this way. How are you supposed to understand what’s going on if you’re not told half the story? I am going to write an angry rant about this.
Glad the new design works for you… it was time!

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Bryan Rowsell

I do the same thing, James! Though I leave out acid/base reactions and use the line “almost all reactions in this course are either acid/base reactions or one of the following three…” as they learn acid/base reactions in freshman chemistry.

You should also check out this paper too: J. Chem. Educ., 2008, 85 (1), p 83. Great, readable paper I give out to my students just at the end of the term to facilitate their studying. If you give it out at the beginning, they won’t understand it and won’t read it.

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james
Bryan Rowsell

I shoulda known you’d have read that paper. Yeesh.

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james

Well, it was a great paper. Thanks for making me aware of it!

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james

Edit: decided to go with ionic bond forming/breaking, don’t want to cause any confusion.

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