States of Matter A Matter of Kinetic Energy
Types of States of Matter • Solid • Liquid • Gas • Plasma • BEC, or Bose-Einstein Condensate • Zero State of Matter • Most Dense
chemwiki.ucdavis.edu/Physical_Chemistry/Physical_Properties_of_Matter/Supercritical_Fluidschemwiki.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 than liquids • Diffusion & Effusion • Diffusion: Spontaneous mixing via random motion • Effusion: Passing through tiny opening
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)
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 (like glass and plastics) • Shape & Volume: Definite • Melting Point: Definite • Density & Incompressibility: High • Diffusion: Low rate (10-6 less than others)
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