thanks a million, please make more videos on naming other than alkanes and more on electron pushing and diagrams. I recommend your channel to all my classmates because THE BEST organic chem tutor on youtube
Nowadays text books have questions like how many constitutional isomers are possible for compounds having a molecular formula CnH2nO, how to answer that? Draw out all of them?
In this video, I only focus on constitutional isomers of alkanes. So to answer your question, you would first need to determine whether you had any degrees of unsaturation using the index of hydrogen deficiency, which I teach in this video: leah4sci.com/degree-of-unsaturation. The IHD will tell you if there are any pi bonds or ring structures in your compound. After that, then yes. You would need to draw out every possible structure. It’s easiest to start with those that are linear and then move on to branched structures.
I got an A in High School... Kept learning from you all throughout university and now doing very well in life. I sincerely appreciate what you're doing! @@Leah4sci
There is a formula for finding the number of stereoisomers, but it’s not that easy or straightforward when it comes to constitutional isomers. What’s easiest is to draw out all of the possibilities, starting with the linear structures and then moving on to branched ones. You also might want to learn how to identify any degrees of unsaturation by watching my video at leah4sci.com/degree-of-unsaturation
Hi Leah, thank you so much for your videos! They're very helpful. One question though where you are talking about CH3CH2CH2-CH3(coming off the third carbon) being a butane, why wouldn't this be a methylpropyl? Why isn't CH3 considered a branch of a methyl group coming off the third carbon from the parent chain? Thanks for your help!
Remember before you name them you want to find your parent chain the longest continuous chain of carbons. Since it is apart of the parent chain it is not considered to be a side chain.
Use the highlighter trick for this. If you can trace your highlighter from the first to last carbon, regardless of how many turns on the molecule, it's considered a continuous chain rather than a branch. If you have to lift your highlighter to catch a branched atom, that's a brach
