General Chemistry Principles and Modern Applications Petrucci Harwood

  • Slides: 10
Download presentation
General Chemistry Principles and Modern Applications Petrucci • Harwood • Herring 8 th Edition

General Chemistry Principles and Modern Applications Petrucci • Harwood • Herring 8 th Edition Chapter 13: Liquids, Solids and Intermolecular Forces Philip Dutton University of Windsor, Canada N 9 B 3 P 4 Prentice-Hall © 2002 (modified 2003 by Dr. Paul Root and 2005 by Dr. David Tramontozzi) Prentice-Hall © 2002 General Chemistry: Chapter 12

Contents 13 -1 13 -2 13 -3 13 -4 13 -5 13 -6 13

Contents 13 -1 13 -2 13 -3 13 -4 13 -5 13 -6 13 -7 13 -8 Intermolecular Forces and some Properties of Liquids Vaporization of Liquids: Vapor Pressure Some Properties of Solids Phase Diagrams Van der Waals Forces Hydrogen Bonding Chemical Bonds as Intermolecular Forces Crystal structures Energy Changes in the Formation of Ionic Crystals Focus on Liquid Crystals Prentice-Hall © 2002 General Chemistry: Chapter 12 2

13 -1 Intermolecular Forces and Some Properties of Liquids • Cohesive Forces – Intermolecular

13 -1 Intermolecular Forces and Some Properties of Liquids • Cohesive Forces – Intermolecular forces between like molecules. • Adhesive Forces – Intermolecular forces between unlike molecules. • Surface Tension – Energy or work required to increase the surface area of a liquid. • Viscosity – A liquids resistance to flow Prentice-Hall © 2002 General Chemistry: Chapter 12 3

Intermolecular Forces Interactions with molecules on each side (surface tension) Prentice-Hall © 2002 Interactions

Intermolecular Forces Interactions with molecules on each side (surface tension) Prentice-Hall © 2002 Interactions with molecules surrounding (viscosity) General Chemistry: Chapter 12 4

Intermolecular Forces Clean glass Oil covered glass Capillary action Prentice-Hall © 2002 Adhesive forces

Intermolecular Forces Clean glass Oil covered glass Capillary action Prentice-Hall © 2002 Adhesive forces between water and glass cause meniscus to form. Hg metallic bonds are stronger than adhesive forces with glass therefore no meniscus forms. General Chemistry: Chapter 12 5

13 -2 Vaporization of Liquids: Vapor Pressure Vaporization occurs more readily with increased temperature,

13 -2 Vaporization of Liquids: Vapor Pressure Vaporization occurs more readily with increased temperature, increased surface area of the liquid and decreased strength of intermolecular forces Prentice-Hall © 2002 General Chemistry: Chapter 12 6

Enthalpy of Vaporization ΔHvap = Hvapor – Hliquid = - ΔHcondensation Vaporization is endothermic

Enthalpy of Vaporization ΔHvap = Hvapor – Hliquid = - ΔHcondensation Vaporization is endothermic (positive ΔH value) Condensation is exothermic (negative ΔH value) Prentice-Hall © 2002 General Chemistry: Chapter 12 7

Boiling Point Mercury manometer Vapor pressure of liquid Pvap independent of Vliq Pvap independent

Boiling Point Mercury manometer Vapor pressure of liquid Pvap independent of Vliq Pvap independent on of Vgas T If liquid is introduced, the change in height is proportional to the vapour pressure of the liquid. High vapour pressures = volatile liquid (ether, acetone) Low vapour pressures = non-volatile liquid (mercury) Prentice-Hall © 2002 General Chemistry: Chapter 12 8

Vapor Pressure and Boiling Point The Critical Point Vapor pressure increases with temperature Prentice-Hall

Vapor Pressure and Boiling Point The Critical Point Vapor pressure increases with temperature Prentice-Hall © 2002 Point at which the liquid and the vapor phases are indistinguishable (the densities of the vapor and liquid become the same) General Chemistry: Chapter 12 9

Clausius-Clapeyron Equation 1 ln P = -A ( )+B T y = m x

Clausius-Clapeyron Equation 1 ln P = -A ( )+B T y = m x ΔHvap A= R +b ΔHvap P 2 1 1 ln =( ) T 1 T 2 P 1 R Prentice-Hall © 2002 General Chemistry: Chapter 12 Clausius-Clapeyron Equation 10