Chapter 12: Liquids, Solids, and Phase Changes

Solid

Rigid structure with definite shape and volume.

Liquid

Indefinite shape, fixed volume, particles glide.

Gas

No definite shape or volume, particles far apart.

Ordered Arrangement

Particles in solids are closely packed and organized.

Total Disorder

Particles in gases have random arrangement.

Elastic Collisions

Particles do not lose speed upon collision.

Surface Tension

Energy needed to increase liquid's surface area.

Viscosity

Resistance of a liquid to flow.

Cohesion

Attraction between like molecules within a substance.

Adhesion

Attraction between different substances' molecules.

Meniscus

Curved surface of liquid in a container.

Capillary Action

Liquid rises in a narrow tube due to adhesion.

Evaporation

Liquid transitions to gas at the surface.

Boiling

Liquid transitions to gas throughout when vapor pressure equals atmospheric pressure.

Vapor Pressure

Pressure of vapor at equilibrium in a closed container.

Dynamic Equilibrium

Rate of condensation equals rate of evaporation.

Intermolecular Forces

Attractions between molecules that hold them together.

Volatile Liquids

Liquids that evaporate quickly due to high vapor pressure.

Temperature Effect on Viscosity

Viscosity decreases as temperature increases.

Pressure Effect on Vapor Pressure

Higher temperature increases vapor pressure.

Fixed Volume

Volume remains constant regardless of shape.

Particle Diagram

Visual representation of particle arrangement in states.

Kinetic Model of Gases

Particles move straight until colliding with walls.

Ion-dipole force

Attraction between an ion and polar molecule.

Dipole-dipole force

Attraction between positive and negative ends of polar molecules.

London dispersion forces

Interactions from temporary dipoles in molecules.

Vapor pressure

Pressure exerted by vapor in equilibrium with liquid.

Boiling point

Temperature where liquid turns to gas.

Intermolecular forces

Forces holding molecules together in a substance.

Crystal lattice

Regular, repeating 3-D arrangement of particles.

Crystalline solid

Solid with a defined atomic arrangement.

Ionic solid

Solid held together by ionic bonds.

Molecular solid

Solid held by intermolecular forces, like ice.

Covalent network solid

Solid with atoms in large covalent networks.

Metallic solid

Solid with metallic bonds, high conductivity.

Amorphous solid

Solid with randomly arranged atoms, no order.

Phase change

Reversible change from one state of matter to another.

Heating curve

Graph showing temperature changes during phase transitions.

Heat of fusion (Hfus)

Energy needed to melt 1 gram of solid.

Melting point

Temperature where solid begins to melt.

Freezing point

Temperature where liquid turns into solid.

Heat of vaporization (Hvap)

Energy required to vaporize liquid at constant temperature.

Sublimation

Solid turns directly into gas without becoming liquid.

Condensation

Gas particles form a liquid by losing energy.

Deposition

Gas turns directly into solid under pressure.

Water Vapor

Gaseous state of water at same temperature as boiling.

Kinetic Energy

Energy of motion; increases causes gas formation.

Joule (J)

SI unit of energy; lifts 1 kg by 1 meter.

Heat of Fusion

Energy needed to melt ice; 334 J/g.

Heat of Vaporization

Energy needed to convert water to steam; 2260 J/g.

Molar Heat of Fusion

Energy to melt 1 mole of ice; 6.01 kJ/mol.

Molar Heat of Vaporization

Energy to vaporize 1 mole of water; 40.7 kJ/mol.

Specific Heat Capacity (Cp)

Heat needed to raise temperature of 1 g by 1°C.

Cp of Water

1.00 cal/g·K; heat capacity of liquid water.

Cp of Ice

0.493 cal/g·K; heat capacity of ice.

Cp of Steam

0.447 cal/g·K; heat capacity of steam.

Heat Energy Calculation

Sum of heat absorbed in multiple stages.

Phase Change Stages

Five stages: heating, melting, heating, vaporizing, heating.

Heat Absorption Stages

Ice heating, melting, water heating, vaporizing, steam heating.

Triple Point

Condition where solid, liquid, and vapor coexist.

Critical Point

Temperature/pressure where only vapor exists.

Volatility

Tendency of a substance to vaporize; diethyl ether most volatile.

Energy to Melt Ice

Energy needed to convert ice at 0°C to water.

Energy to Vaporize Water

Energy needed to convert water at 100°C to steam.

Energy to Raise Temperature

Energy needed to increase water temperature to boiling.

Energy to Convert Ice to Water

Energy needed to raise ice from -6°C to 25°C.

Heat Equation

q = m ∆T Cp; calculates heat transfer.

Heat of Fusion Calculation

q = m ∆Hf; calculates melting energy.