States of Matter

A Matter of Kinetic Energy

Types of States of Matter

• Solid• Liquid• Gas• Plasma• Beam• BEC, or Bose-Einstein Condensate– Zero State of Matter– Most Dense

Changes of State

Kinetic Energy (kelvins & paschals)

chemwiki.ucdavis.edu/Physical_Chemistry/Physical_Properties_of_Matter/Supercritical_Fluids

• Supercritical fluids are useful in science today – extraction of floral fragrance – the process of creating decaffeinated coffee– food science and functional food ingredients– pharmaceuticals, cosmetics, polymers, powders,

bio- and functional materials – nano-systems, natural products, biotechnology,

fossil & biofuels, microelectronics & environment (Bottini 133).

www.engineeringtoolbox.com/vapor-steam-d_609

• Superheated Vapor• When the temperature is higher than the boiling

point @ a given pressure. • Vapor cannot exist in contact with the fluid, nor

contain fluid particles. • Increase in pressure or decrease in temperature will

not, within limits, condensate out liquid particles in the vapor.

• Highly superheated vapors are gases that approximately follow the general gas law.

Critical Temp & Pressure

• Critical Temperature– The temperature at which only gas exists,

regardless of its pressure• Critical Pressure– The lowest pressure at which liquids exist at

critical temperature • Critical Point– The intersection of critical temperature & pressure

Kinetic-Molecular Theory of Gases

• Ideal gas = hypothetical gas perfectly aligns with all kinetic-molecular theory assumptions

• Five Assumptions– Distance between molecules dwarfs actual size– All collisions are perfectly elastic– Particles are in continuous, rapid, random motion– Particles have NO attraction to each other– Temperature = average kinetic energy of particles

Nature of Gases

• Ideal vs. Real– Real approaches ideal @ low pressure/ high temp

• Expansion – molecules fill entire space• Fluidity – no intermolecular attractions• Density - ~ 10-3 of liquid or solid state• Compressibility – 100X more molecules• Diffusion & Effusion– Spontaneous mixing via random motion– Passing through tiny opening

C/C Intermolecular Forces

Properties of Liquids• LEAST common state of matter in universe• Fluids (as are gases)• Lower kinetic energy than gases• Interactive forces keep molecules connected– Dipole-dipole forces • Equal but opposite charges separated by short distance

– London dispersion forces • Spontaneous creation of dipoles (polar & nonpolar)

– Hydrogen bonding (electronegativity)

Hydrogen Bonding

Properties of Liquids, continued

• Density: 100x > gases; 10% < solids• Compressibility: @ 103 atm., volume ~ 4% • Diffusion: present, but slower than in gases• Surface tension: high intermolecular attraction• Capillary action: attraction between surfaces

of liquid and a solid• Vaporization: evaporation & boiling gas

Nature of Solids• Interparticle attractions stronger than others• Two types of solids– Crystalline (orderly arrangement)– Amorphous (random arrangement)

• supercooled liquids: have liquid properties even if look solid

• Shape & Volume: Definite• Melting Point: Definite• Density & Incompressibility: High• Diffusion: Low rate (10-6 less than others)

Dipole-dipole Forces

Covalent Molecular Structures

Buckminsterfullerene Glucose – C6H12O6

Crystalline Solids• Ionic

• Alkali & alkaline earth with halogens & Group 16• Hard, brittle, high melting points, good insulators

• Covalent network• Cx (diamonds), (SiO2)x quartz, (SiC)x

• Very hard and brittle, high MP, semi- or nonconductors

• Covalent molecular (nonpolar & polar)• H2, CH4, C6H6: only weak London dispersion forces

• H2O & NH3,: stronger forces but weaker than covalent• Soft, low MP, low BP, good insulators

Crystalline Structures

AgCl Ionic Structure

Covalent Network Crystals

Diamond Quartz

Covalent Network

GraphiteCarbon

Covalent Molecular