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Unformatted text preview: ipole-induced dipole
London dispersion forces 0.05-40
For liquid and solid：
Ion-dipole > Hydrogen bond > Dipole-dipole > IonIonHydrogen
DipoleIoninduced dipole > Dipole-induced dipole
Dipole- Sample Exercise 11.1 Comparing Intermolecular Forces
The dipole moments of acetonitrile, CH3CN, and methyl iodide, CH3I,
are 3.9 D and 1.62 D, respectively. (a) what kinds of intermolecular
forces exist among their molecules respectively? (b) Which of these
substances has greater dipole–dipole attractions among its
molecules? (c) Which of these substances has greater London
dispersion attractions? (d) The boiling points of CH3CN and CH3I
are 354.8 K and 315.6 K, respectively. Which substance has the
greater overall attractive forces?
(b) Dipole–dipole attractions increase as the dipole moment of the
CH3CN has a greater dipole–dipole attractions among its molecules
(c) The more massive molecule generally has the stronger dispersion
CH3I : 142.0 g/mol
CH3I : 354.8K
CH3CN: CN: ?g/mol
CH3CN: 315.6K Sample exercises: List the following substances in an order of
increasing boiling points: BaCl2, H2, CO, HF and Ne The
The boiling point depends in part on the intermolecular
forces in the liquid
BaCl2, H2, CO, HF , Ne 2 28 20 20 BaCl2, >
Boiling Points: 1813K HF > CO
293K 83K > Ne > H2 27K 20K Properties
Properties of the Liquid
The forces that hold a liquid together result in
- Resistance to flow.
Surface Tension - Attraction of molecules at the
Vapor Pressure - Ability for molecules to escape
from a liquid.
- When the vapor pressure is
the same as atmospheric (1 atm). Viscosity
Viscosity-The Properties of Liquids
Viscosity: the resistance of a liquid to flow
Viscosity describes a fluid's internal resistance to flo...
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This document was uploaded on 02/26/2014.
- Fall '14