If you ask any former organic student about the key to O-Chem, their answer will surely mention practice problems. “Organic chemistry is all about practice problems, practice problems, and more practice problems,” says one former Orgo student. However, practice problems are only helpful if you can eventually learn how to solve it…
Meet Dave. Dave is an organic chemistry student who’s spent the last 30 minutes trying to solve a homework question. He’s frustrated, and finally gives up. He turns to the back of the book, and this is what he sees:
…and that’s it. No explanation. No mechanism. Not even a pat on the back.
As a former organic chemistry student, I can tell you that this is the worst. You get even more frustrated, and you certainly don’t learn.
Enter our Orgo Made Simple promise: We will NEVER leave you stranded on a practice problem found on our site. Ever. Every answer is fully explained with many solutions having figures detailing the steps to the correct answer.
Don’t be frustrated, like Dave. Get practice problems that truly help you learn organic chemistry with Orgo Made Simple.
Example Practice Problems
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Take a test run with a few Orgo Made Simple practice problems. All questions are presented in this same format throughout the OMS material.
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Question 1 of 2
We choose the longest, continuous chain of carbons as our parent chain, which is 6 carbons long, so it’s named as hexane. Anything not in the parent chain is a substituent, and there are two substituents in this molecule. The parent chain is numbered from left to right to minimize the numbering of substituents. On carbon 2, there is an iodine substituent (named as 2-iodo), and on carbon 4, there is a chlorine substituent (named as 4-chloro). Putting the entire name together and placing the substituents in alphabetical order, the name of the molecule is 4-chloro-2-iodohexane.
Question 2 of 2
Draw resonance structures for the following molecule with curved arrows, and indicate the best resonance structure.Correct
We can first break the carbon-oxygen double bond, which is a situation we can form a resonance structure. We use a single curved arrow on the first structure to show the breaking of the carbon-oxygen double bond, which places a negative charge on the oxygen and a positive charge on the carbon.
The second resonance structure fits the resonance pattern of “An area of high electron density next to an area of low electron density.” We use a single arrow to show the double bond moving to the positive charge.
As a final check, ensure the overall charge of each resonance structure is the same. In both molecules, the overall charge is neutral (0).
The best structure is the one that has full octet on each atom, while minimizing the amount of charge on its atoms as much as possible. The two resonance structures on the right do not have full octets where the positive charge is located, which greatly weakens these resonance structures. As a result, the far left molecule is the best resonance structure, making it the largest contributor to the resonance hybrid.