Evaporation

[UFiA0389]

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Why does ether evaporate before toluene?? I'm getting a little confused between what has higher boiling point and and what has higher melting point

 

[herkulease]

ether evaporates before toluene because it has a lower boiling point.

toluene bp is 110 C

ether or diethyl either is only about 34 C.

toluene has a melting point of -93 C

ether mp is -116 C

toluene has both a higher melting and boiling point than ether.

 

[KyoPhan]

Did it say what kind of ether?

 

[UFiA0389]

Did it say what kind of ether?

its a diethyl ether and toulene mixture

 

[KyoPhan]

its a diethyl ether and toulene mixture

The higher it's molecular weight, the higher it's boiling point. Diethyl ether has 4 C and 1 O, while tolune has 7C.
So diethyl ether has molecular weight of aprox 64 and toluene 84. (Ignored the hydrogens)
Tolune has higher molecular weight, meaning it's boiling point is higher.

Things to consider for boiling point:
1) Molecular weight
2) Intermolecular force
Ionic > Hydrogen bonding > dipole dipole > Van der Waals dispersion forces.
Hydrogen bond are usually a good indicator that the boiling point is really high. Way you can remember is that water has a 100 degree celcius boilinlg point. Very high despite it's really low molecular weight.
3) Symmetry and branching

 

[UFiA0389]

Thanks!!!!