Solving Serial Dilutions | MCAT Content 

Thank you!!! Glad you are finding the videos helpful.

Glad you are finding the videos helpful! Orgo is kinda weird on the MCAT in the sense that it isn’t that similar to what you are expected to know in college. While I will eventually make videos on this topic it is probably going to be a while since I have a video backlog at present. The most important things to know for the MCAT are the lab techniques, nomenclature and stereochemistry, functional groups and their properties (polarity, general types of reactions they undergo, naming, etc.), and lastly being able to trace out how reactions are occurring on the basis of a given reaction scheme (this skill is way more important than knowing all of the various reactions and arrow pushing mechanisms are practically useless on the MCAT.)

Your welcome! Glad the video was helpful.

Thanks for the tip I will definitely give that a try. I have gotten some feedback that I talk too fast. I script all of the videos to make sure that I don’t go off topic and hit all of the points I want to, but since I am essentially just reading what I have already written I don’t have to think and talk at the same time so I can speed through the material too quickly at times. I am experimenting to try and figure out the right speed which is a lot harder than I thought it would be.

I think I see why. In your earlier examples you showed three flasks of different volume but only focused on the one of known concentration and volume, and the one which has the new mixture. At the 7:00 mark the dilution factor is 2:3 (instead of 2:5) because you did not show the 1 mL solution you must have mixed the initial 2mL one with. The same logic describes the second dilution factor. Did I figure it out?

In the dilution you are referencing the final volumes of the solutions were given rather than the amount that was added. So in the first dilution you started with 2 mL and it was diluted to a total volume of 3 mL so it would stay as a 2:3 dilution in the second dilution the same thing occurred. In the second dilution it is the same. The final volume of 40 mL was given so it would also be a 0.01 : 40 dilution. The difference between this dilution and the last one is that in the previous ones the final volume wasn’t given and had to be calculated based on the amount of solution that was added. The AAMC can ask dilutions both ways: giving you the amount added or the final amount, just make sure you are careful about identifying which type of information is given and always find the final solution volume since that is the one that counts!