Chapter 10 States of matter
Kinetic Molecular Theory • Particles of matter are in constant motion
The state of a substance at room temperature depends on the strength of the intermolecular forces between the particles.
5 assumptions of Kinetic Theory • 1. gases are tiny particles • 2. particles have elastic collisions with each other • 3. particles in constant motion • 4.no forces between particles • 5. speed of particles determined by temperature
Bonding (Intramolecular) ionic bond- transfer of electrons between cation (+) and anion(-) Subtract electronegativities to predict bond type
Covalent bond- sharing of electrons • Nonpolar- equal sharing of electrons • Polar –unequal sharing of electrons
Polar molecule has a slightly + and – side due to the difference in electronegativities of the elements involved.
Intermolecular forces • Occur between 2 molecules (polar covalent) • 3 major types: 1.dispersion • 2. dipole to dipole 3. hydrogen bond
Dispersion force- temporary and weak strong polar molecule causes a nonpolar molecule to become slightly polar
Dipole to Dipole • slightly + end of one molecule is attracted to the slightly – end of another molecule • Shape can cancel out polarity
Hydrogen bond- attraction between molecules • Uses H,F, O, N. (generally the strongest attraction)
Fluidity, expansion, diffusion occur due to the weak or none attraction between molecules • Which states of matter have these properties?
Diffusion Rates • Which diffuses faster? • High molar mass or low molar mass? • Polar or nonpolar molecules? • High IMF or low IMF?
Ideal gases have NO attraction between molecules • Real gases have some attraction between molecules
A change of state occurs when IMF are formed or broken • Increase in heat? • Decrease in heat?
Changing gases into liquids • Increase pressure • Decrease temperature • This causes increase in IMF
Liquids Viscosity- resistance of a liquid to flow examples: IMF high or low? generally polar or nonpolar? Effect of heat?
Surface tension- causes surface area to decrease in size- due to IMF • IMF high or low? • Effect of heat? Polar or nonpolar liquids?
Capillary action- movement of water in a tube • -due to attraction between tube and liquid • Adhesion is greater than cohesion
Cohesion- attraction between the particles • Adhesion- attraction of the particles to the outside surface
Water beads on the car • Which is greater adhesion or cohesion?
Evaporation-rate depends on IMF between molecules and the KE of the molecules High evaporation rate- low IMF or high IMF? High Evaporation Rate- high or low KE? Increase in tempwhat?
Volatile – evaporates easily • IMF strong or weak? • Nonvolatile– does not evaporate easily • IMF strong or weak?
Importance of perspiration? When water evaporates from a solution, does the solution become more or less concentrated?
expansion • What type of IMF (low or high) allows for the most expansion?
Slow diffusion • Low or high IMF? • Increase in Temperature causes the diffusion rate to increase or decrease?
solidification • Liquids tend to solidify when the temperature decreases. Why?
Polar liquids (review) • Have: strong IMF • high viscosity • high boiling point • low rate of evaporation • high surface tension • low expansion
Exothermic- releases heat • Endothermic- requires heat
Process endo/exo Imf example • Melting- • Freezing • Condensation • Vaporization • Sublimation • Deposition
Boiling point of a liquid is when the vapor pressure is equal to the atmospheric pressure. An increase in the atmospheric pressure increases the boiling point.
examples • Pressure Cookers- • Lid increases pressure inc. Boiling point • Decreases cooking time
examples • Cooking on Pikes Peak • Decrease atm press decreases BP increases cooking time
Phase Diagram • Triple point- the temperature and pressure required for all 3 states can co-exist in equilibrium
Molar Heat of Fusion • Heat needed to melt one mole of a solid at its melting point
Molar Heat of Vaporization • Amount of heat needed to vaporize one mole of a liquid at its boiling point
Name the state of matter Definite shape, definite volume No definite shape or volume Definite volume, no definite shape