Aula #14

Intermolecular Forces Liquids and Solids

Covalent networks

e.g. diamond

Strong interactions

Ionic networks

Cation +…Anion -

Metallic bond

Weak interactions

Intermolecular Forces Liquids and Solids

.. interactionsH - bond

Attractive interactions: Summary

Intermolecular Forces Liquids and Solids

Typical phase diagram …Pure substance

Intermolecular Forces Liquids and Solids

Intermolecular Forces Liquids and Solids

Hydrogen bondingPolymers

Kevlar hydrogen bonding Cellulose hydrogen bonding

Intermolecular Forces Liquids and Solids

Hydrogen Bond

Intermolecular Forces Liquids and Solids

Hydrogen bonding2 H-Bond Dimmer

Hydrogen bonding4 H-Bond Dimmer

Intermolecular Forces Liquids and Solids

Hydrogen bondingPolymers

Kevlar hydrogen bonding Cellulose hydrogen bonding

Intermolecular Forces Liquids and Solids

Effect of Hydrogen Bonding on Boiling Points

Intermolecular Forces Liquids and Solids

Interface between Liquids

hexane to water,

Mixtures of Liquids

Intermolecular Forces Liquids and Solids

& at the surface

Surface tension ….is the amount of energy required to stretch or increase the surface of a liquid by a unit area.

Strong intermolecular forces > High surface tension

Surface tension ….is the amount of energy required to stretch or increase the surface of a liquid by a unit area.

Strong intermolecular forces > High surface tension

Intermolecular Forces Liquids and Solids

& at the surface

Surface tension ….is the amount of energy required to stretch or increase the surface of a liquid by a unit area.Strong intermolecular forces > High surface tension

Change of the surface tension.. Presence of a surfactantSurfactant

Sodium Laureth Sulfate

Intermolecular Forces Liquids and Solids

& at the surface

Intermolecular Forces Liquids and Solids

& at the surface

They

Adhere, adsorb, make bubbles, aggregate

Intermolecular Forces Liquids and Solids

& transport properties

Demonstration …surface tension