Chemistry Test Chapters 10/11

kinetic-molecular theory

kinetic-molecular theory

description of matter as particles in motion

temperature

average kinetic energy of particles

gases

particle size - small, mostly empty space, particles are far apart, only a few atoms (O2)

particle motion - constantly moving in a straight line until a collision with a solid or another gas particle

particle energy - particles can move at different velocities, smaller mass takes less energy to move and vice versa

behavior - low density, can compress and expand

diffusion

one gas mixes with another gas

effusion

gas released through a small opening

pressure

force per unit area (air pressure, barometer)

intramolecular forces

-strongest

-ionic bonds (+/-)

-covalent bonds (shared electrons)

-metallic bonds (electron sea model)

intermolecular forces

-weaker

-dispersion forces

-dipole-dipole forces

-hydrogen bonds

dispersion forces

-temporary shifts in electron clouds in nonpolar molecules

-attraction between temporary dipoles

-stronger based on number of electrons

dipole-dipole forces

-attraction between permanent dipoles in polar molecules

-can be strong in small molecules with large dipoles (electronegativity difference)

-generally weaker than dispersion forces

hydrogen bonds

-special dipole-dipole bonds formed when H is bonded to F, O, or N

-generally strongest intermolecular forces

liquids

-density and compression (more dense than gases, almost never compress)

-fluid (flow - fill a space, diffuse - movement of one liquid through another)

-cohesion (liquid + liquid) and adhesion (liquid + other) (force of attraction between molecules)

-meniscus (water molecules attract each other - cohesion, dip - and glass molecules - adhesion, raised)

viscosity

-resistance to flowing that a fluid has

-intermolecular forces (stronger = molecules closer together = harder to flow)

-size and shape of particles (larger particles = harder to flow, long particles drag/catch)

-temperature (higher temp = atoms move faster = flow faster)

surface tension

layer of intermolecular forces are stronger, creating tension

solids

-follow kinetic molecular theory (still move)

-density and compression (more dense than liquids)

crystalline solids

atomic (dispersion forces holding together elements that otherwise would not bond)

molecular (all 3 forces allow molecules to be pulled together)

covalent network (molecules form solids from repeated covalent bonds)

ionic (positive-negative repeated bonds)

metallic (formed from metallic bonds)

allotrope

single solid forms different structures

amorphous solid

no order or pattern in molecules, rapidly cooled into solids

phase changes

melting (solid to liquid) require energy

vaporization (liquid to gas) require energy

deposition (gas to solid) release energy

freezing (liquid to solid) release energy

condensation (gas to liquid) release energy

sublimation (solid to gas) require energy

triple point

specific temp and pressure where a substance can exist as all 3 types of matter simultaneously