Hi Hussein Murad, I'll let the team know, as of right now our team is focusing on getting a new practice final up before finals. 

Marte Medina 

There are more examples of this topic in the below video, at timestamp 18:06

Recall we want the substituents to be at the lowest numbers possible. We cannot have them be at 1, 3 and 4 when the lowest is already 1,2 and 4. 

Both orders will give you the correct answer, if your professor mentioned this specific order then I recommend following that. 

Shazabe Siddique No, but you'll find timestamps to each question in the description of this video. You'll find that on each study with us (green) video. 

Yes you'll find naming using R and S systems here: 

Naming Video

Meso compounds and other isomers:

Types of Isomers

Practice problems on stereoisomers and isomers

Everything on Stereochemistry can be found in the below category: 

Stereochemistry 

Yes you could have done that too.

As long as you number the chairs for the chair flip in the same direction (clockwise or counterclockwise) and move 1 carbon over for the second chair, then yes that is fine. As mentioned there are several different ways you can number the chair. 

Recall alkyl groups are substituents that consist of only C and H. So by larger alkyl groups, that means carbon chains that have more than 1 carbon in them. Like ethyl, isopropyl, butyl etc. The more carbons it has the larger it is. 

If anyone is unsure of question 10 and why hybridization wins here instead of electronegativity, we can compare pKa values and see that the terminal alkyne (An alkyne that is at the end of the carbon chain) has a lower pKa value compared to the amine and therefore is more acidic.