Boiling point, !

  • #1
Boiling point, urgent !

Which of the following has higher boiling point?
1) Mixture of hexane and propanone
2) propapone
(consider their relative molecular mass and the forces of attraction between the molecules)

I think the mixture of hexane and propanone has a higher boiling point, as propanone has lone pair electrons, therefore the force between the molecules in the mixture is dipole-induced dipole, while the force exists between pure propanone molecules is instantaneous diple-induced dipole.

However my classmate told me the mixture has a lower boiling point and was confirmed by my teacher.

I hope I can get your answer in 3 to 4 hours, if not, it's ok and I'll treat this thread as a discussion. Thanks in advance.

PS. This question is for the theory part of my lab. report. Since the data obtained was ridiculous, that's why I need to know the fact.

PS2. I need to finish it in 4.5 hours.
 

Answers and Replies

  • #2
53
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The boiling point of Propane is -42degrees
The boiling point of Hexane is 69 degrees

I think you might be right Mrs Kam
 
  • #3
I think you might be right Mrs Kam
Mrs Kam ??!! I'm not Mrs Kam.

Propane : C3H8
propanone : CH3C=OCH3

In fact, i need to draw a graph, variation of boiling point against % composition by volume haxane/propanone mixture. (This is an experiment on phase equilibrium)
 
Last edited:
  • #4
92
0
acetone

hexane: 68.7
acetone: 56.5

sounds like a boring lab
 
  • #5
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The word "azeotrope" should appear somewhere in the background material for the lab. Prediction of "azeotropes" is a topic for the M&PS forum.
 
  • #6
Originally posted by myself
I think the mixture of hexane and propanone has a higher boiling point, as propanone has lone pair electrons, therefore the force between the molecules in the mixture is dipole-induced dipole, while the force exists between pure propanone molecules is instantaneous diple-induced dipole.
Um..this is wrong. The force between molecules in pure propanone(acetone) is dipole-dipole interaction, since there are 2 lone pair electrons. The bond between molecules in pure hexane is instantaneous dipole-induced dipole. If they are mixed together, hexane molecules will destroy the dipole-dipole interaction between propanone molecules and to form a diple-induced dipole interatction.


Thanks for your help.
 

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