This question is testing you on your application of the basic concepts that you should have leanred in Organic Chemistry chapters.

The last two alkanes should be very very long. Personally i have only heard of this long chain why i was working with Dr. Wu Jishan from NUS-Dept of Chemistry. I read and understand that he has been researching on the many special properties of Pentacontane.

http://www.chemistry.nus.edu.sg/ourpeople/_files/Full%20Publications%20List-wu%20js.pdf

But you dont need all the tough chemistry to predict the boiling points of Pentacontane.

Based on the basic essential concepts that i have taught you in June’s Chemistry Intensive Revision Bootcamp, we know that boiling points are affected by the weak Van der Waals forces of attraction holding covalent molecules together.

Pentacontane is an alkane and thus a covalent molcule. For covalent molecules, the greater the chain length for molecule, the larger the amount of many weak Van der Waals forces acting between many molecules. As such, more heat energy is required to break the Van der Waals forces, before the molecules can break free and become gaseous. This means boiling points increases.

If question ask: “Why there is no boiling points for Pentacontane?”, then the answer must be around the fact that Pentacontane is a very long alkane molecule and they are too many Van der Waals forces acting between those molecules. This prevent the molecules to change from liquid state to gaseous state. Thus, no boiling points for Pentacontane.

PS: Pentacontane is a long alkane molecule made up of 50 Carbon atoms.

This applies to tetrachontane also.

Hope this explanation is useful to you!

To Your Academic Success in Chemistry,
Sean Chua
Master Trainer
http://www.SimpleChemConcepts.com

heres a question that i need your help.

Suggests two reasons why there are no values given for the boiling points of the last 2 alkanes, tetrachontane and pentacontane.

Thanks Sean.

I am glad you love this chemistry blog-site.

Thanks for your encouragement. Certainly gives me more purpose on maintaining this blog as the best resource for those studying basic Chemistry.

Hope to hear more from you. Take Care.

Rgds
Sean
Master Trainer
http://www.SimpleChemConcepts.com