I. Intermolecular Forces (Ch. 6, p.189-193) Ch. 12 - Liquids & Solids I. Intermolecular Forces (Ch. 6, p.189-193)

A. Definition of IMF Attractive forces between molecules. Much weaker than chemical bonds within molecules.

B. Types of IMF

B. Types of IMF London Dispersion Forces View animation online.

B. Types of IMF Attractive forces that arise as a result of temporary dipoles induced in atoms or molecules ion-induced dipole interaction dipole-induced dipole interaction 11.2

B. Types of IMF Dipole-Dipole Forces + - View animation online.

B. Types of IMF Hydrogen Bonding

C. Determining IMF NCl3 polar = dispersion, dipole-dipole CH4 nonpolar = dispersion HF H-F bond = dispersion, dipole-dipole, hydrogen bonding

II. Physical Properties (p. 363 - 371) Ch. 12 - Liquids & Solids II. Physical Properties (p. 363 - 371)

A. Liquids vs. Solids IMF Strength Fluid Density Compressible Diffusion LIQUIDS Stronger than in gases Y high N slower than in gases SOLIDS Very strong N high extremely slow

A. Liquids vs. Solids A phase is a homogeneous part of the system in contact with other parts of the system but separated from them by a well-defined boundary.

B. Liquid Properties Surface Tension attractive force between particles in a liquid that minimizes surface area

B. Liquid Properties Capillary Action attractive force between the surface of a liquid and the surface of a solid water mercury

B. Liquid Properties Adhesion Cohesion

Water is a Unique Substance Maximum Density 40C Density of Water Water is a Unique Substance 11.3

C. Types of Solids Crystalline - repeating geometric pattern covalent network metallic ionic covalent molecular Amorphous - no geometric pattern decreasing m.p.

C. Types of Solids Ionic (NaCl) Metallic

C. Types of Solids Covalent Molecular Covalent Network Amorphous (H2O) (SiO2 - quartz) Amorphous (SiO2 - glass)

C. Types of Solids Diamond Graphite

C. Types of Solids

III. Changes of State (p. 372 - 382) Ch. 12 - Liquids & Solids III. Changes of State (p. 372 - 382)

A. Phase Changes

A. Phase Changes Evaporation molecules at the surface gain enough energy to overcome IMF Volatility measure of evaporation rate depends on temp & IMF

Greatest Order Least T2 > T1 Evaporation Condensation

A. Phase Changes temp volatility IMF volatility Boltzmann Distribution # of Particles volatility IMF volatility Kinetic Energy

A. Phase Changes Equilibrium trapped molecules reach a balance between evaporation & condensation

A. Phase Changes Vapor Pressure pressure of vapor above a liquid at equilibrium depends on temp & IMF directly related to volatility

A. Phase Changes IMF v.p. v.p. temp

A. Phase Changes Patm b.p. IMF b.p. Boiling Point temp at which v.p. of liquid equals external pressure depends on Patm & IMF Normal B.P. - b.p. at 1 atm Patm b.p. IMF b.p.

A. Phase Changes IMF m.p. Melting Point equal to freezing point Which has a higher m.p.? polar or nonpolar? covalent or ionic? polar ionic

A. Phase Changes Sublimation solid  gas v.p. of solid equals external pressure EX: dry ice, mothballs, solid air fresheners

B. Heating Curves Gas - KE  Boiling - PE  Liquid - KE  Melting - PE  Solid - KE 

B. Heating Curves Heat of Vaporization (Hvap) energy required to boil 1 gram of a substance at its b.p. usually larger than Hfus…why? EX: sweating, steam burns, the drinking bird

B. Heating Curves Temperature Change change in KE (molecular motion) depends on heat capacity Heat Capacity energy required to raise the temp of 1 gram of a substance by 1°C

B. Heating Curves Phase Change change in PE (molecular arrangement) temp remains constant Heat of Fusion (Hfus) energy required to melt 1 gram of a substance at its m.p.

C. Phase Diagrams Show the phases of a substance at different temps and pressures.

C. Phase Diagrams